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Scholtysek L, Poetsch A, Hofmann E, Hemschemeier A. The activation of Chlamydomonas reinhardtii alpha amylase 2 by glutamine requires its N-terminal aspartate kinase-chorismate mutase-tyrA (ACT) domain. PLANT DIRECT 2024; 8:e609. [PMID: 38911017 PMCID: PMC11190351 DOI: 10.1002/pld3.609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/08/2024] [Accepted: 05/16/2024] [Indexed: 06/25/2024]
Abstract
The coordination of assimilation pathways for all the elements that make up cellular components is a vital task for every organism. Integrating the assimilation and use of carbon (C) and nitrogen (N) is of particular importance because of the high cellular abundance of these elements. Starch is one of the most important storage polymers of photosynthetic organisms, and a complex regulatory network ensures that biosynthesis and degradation of starch are coordinated with photosynthetic activity and growth. Here, we analyzed three starch metabolism enzymes of Chlamydomonas reinhardtii that we captured by a cyclic guanosine monophosphate (cGMP) affinity chromatography approach, namely, soluble starch synthase STA3, starch-branching enzyme SBE1, and α-amylase AMA2. While none of the recombinant enzymes was directly affected by the presence of cGMP or other nucleotides, suggesting an indirect binding to cGMP, AMA2 activity was stimulated in the presence of L-glutamine (Gln). This activating effect required the enzyme's N-terminal aspartate kinase-chorismate mutase-tyrA domain. Gln is the first N assimilation product and not only a central compound for the biosynthesis of N-containing molecules but also a recognized signaling molecule for the N status. Our observation suggests that AMA2 might be a means to coordinate N and C metabolism at the enzymatic level, increasing the liberation of C skeletons from starch when high Gln levels signal an abundance of assimilated N.
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Affiliation(s)
- Lisa Scholtysek
- Faculty of Biology and Biotechnology, PhotobiotechnologyRuhr University BochumBochumGermany
| | - Ansgar Poetsch
- Faculty of Biology and Biotechnology, Department for Plant BiochemistryRuhr University BochumBochumGermany
- School of Basic Medical SciencesNanchang UniversityNanchangChina
| | - Eckhard Hofmann
- Faculty of Biology and Biotechnology, Protein CrystallographyRuhr University BochumBochumGermany
| | - Anja Hemschemeier
- Faculty of Biology and Biotechnology, PhotobiotechnologyRuhr University BochumBochumGermany
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2
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Amala M, Nagarajan H, Ahila M, Nachiappan M, Veerapandiyan M, Vetrivel U, Jeyakanthan J. Unveiling the intricacies of allosteric regulation in aspartate kinase from the Wolbachia endosymbiont of Brugia Malayi: Mechanistic and therapeutic insights. Int J Biol Macromol 2024; 267:131326. [PMID: 38569988 DOI: 10.1016/j.ijbiomac.2024.131326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 03/04/2024] [Accepted: 03/31/2024] [Indexed: 04/05/2024]
Abstract
Aspartate kinase (AK), an enzyme from the Wolbachia endosymbiont of Brugia malayi (WBm), plays a pivotal role in the bacterial cell wall and amino acid biosynthesis, rendering it an attractive candidate for therapeutic intervention. Allosteric inhibition of aspartate kinase is a prevalent mode of regulation across microorganisms and plants, often modulated by end products such as lysine, threonine, methionine, or meso-diaminopimelate. The intricate and diverse nature of microbial allosteric regulation underscores the need for rigorous investigation. This study employs a combined experimental and computational approach to decipher the allosteric regulation of WBmAK. Molecular Dynamics (MD) simulations elucidate that ATP (cofactor) and ASP (substrate) binding induce a closed conformation, promoting enzymatic activity. In contrast, the binding of lysine (allosteric inhibitor) leads to enzyme inactivation and an open conformation. The enzymatic assay demonstrates the optimal activity of WBmAK at 28 °C and a pH of 8.0. Notably, the allosteric inhibition study highlights lysine as a more potent inhibitor compared to threonine. Importantly, this investigation sheds light on the allosteric mechanism governing WBmAK and imparts novel insights into structure-based drug discovery, paving the way for the development of effective inhibitors against filarial pathogens.
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Affiliation(s)
- Mathimaran Amala
- Structural Biology and Biocomputing Lab, Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Hemavathy Nagarajan
- Structural Biology and Biocomputing Lab, Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Mathimaran Ahila
- Structural Biology and Biocomputing Lab, Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Mutharasappan Nachiappan
- Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Road, New Delhi 110 067, India
| | - Malaisamy Veerapandiyan
- Structural Biology and Biocomputing Lab, Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Umashankar Vetrivel
- Virology & Biotechnology/Bioinformatics Division, ICMR-National Institute for Research in Tuberculosis, Chennai, Tamil Nadu 600 031, India
| | - Jeyaraman Jeyakanthan
- Structural Biology and Biocomputing Lab, Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil Nadu, India.
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3
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Fang H, Shan T, Gu H, Chen J, Qi Y, Li Y, Saeed M, Yuan J, Li P, Wang B. Identification and characterization of ACR gene family in maize for salt stress tolerance. FRONTIERS IN PLANT SCIENCE 2024; 15:1381056. [PMID: 38745920 PMCID: PMC11091409 DOI: 10.3389/fpls.2024.1381056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/15/2024] [Indexed: 05/16/2024]
Abstract
Background Members of the ACR gene family are commonly involved in various physiological processes, including amino acid metabolism and stress responses. In recent decades, significant progress has been made in the study of ACR genes in plants. However, little is known about their characteristics and function in maize. Methods In this study, ACR genes were identified from the maize genome, and their molecular characteristics, gene structure, gene evolution, gene collinearity analysis, cis-acting elements were analyzed. qRT-PCR technology was used to verify the expression patterns of the ZmACR gene family in different tissues under salt stress. In addition, Ectopic expression technique of ZmACR5 in Arabidopsis thaliana was utilized to identify its role in response to salt stress. Results A total of 28 ZmACR genes were identified, and their molecular characteristics were extensively described. Two gene pairs arising from segmented replication events were detected in maize, and 18 collinear gene pairs were detected between maize and 3 other species. Through phylogenetic analysis, three subgroups were revealed, demonstrating distinct divergence between monocotyledonous and dicotyledonous plants. Analysis of ZmACR cis-acting elements revealed the optional involvement of ZmACR genes in light response, hormone response and stress resistance. Expression analysis of 8 ZmACR genes under salt treatment clearly revealed their role in the response to salt stress. Ectopic overexpression of ZmACR5 in Arabidopsis notably reduced salt tolerance compared to that of the wild type under salt treatment, suggesting that ZmACR5 has a negative role in the response to salt stress. Conclusion Taken together, these findings confirmed the involvement of ZmACR genes in regulating salt stress and contributed significantly to our understanding of the molecular function of ACR genes in maize, facilitating further research in this field.
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Affiliation(s)
- Hui Fang
- Ministry of Agricultural Scientific Observing and Experimental Station of Maize in Plain Area of Southern Region, School of Life Sciences, Nantong University, Nantong, Jiangsu, China
| | - Tingyu Shan
- Ministry of Agricultural Scientific Observing and Experimental Station of Maize in Plain Area of Southern Region, School of Life Sciences, Nantong University, Nantong, Jiangsu, China
| | - Haijing Gu
- Ministry of Agricultural Scientific Observing and Experimental Station of Maize in Plain Area of Southern Region, School of Life Sciences, Nantong University, Nantong, Jiangsu, China
| | - Junyu Chen
- Ministry of Agricultural Scientific Observing and Experimental Station of Maize in Plain Area of Southern Region, School of Life Sciences, Nantong University, Nantong, Jiangsu, China
| | - Yingxiao Qi
- Ministry of Agricultural Scientific Observing and Experimental Station of Maize in Plain Area of Southern Region, School of Life Sciences, Nantong University, Nantong, Jiangsu, China
| | - Yexiong Li
- Ministry of Agricultural Scientific Observing and Experimental Station of Maize in Plain Area of Southern Region, School of Life Sciences, Nantong University, Nantong, Jiangsu, China
| | - Muhammad Saeed
- Department of Agricultural Sciences, Government College University, Faisalabad, Pakistan
| | | | - Ping Li
- Ministry of Agricultural Scientific Observing and Experimental Station of Maize in Plain Area of Southern Region, School of Life Sciences, Nantong University, Nantong, Jiangsu, China
| | - Baohua Wang
- Ministry of Agricultural Scientific Observing and Experimental Station of Maize in Plain Area of Southern Region, School of Life Sciences, Nantong University, Nantong, Jiangsu, China
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Liu J, Liu J, Li J, Zhao X, Sun G, Qiao Q, Shi T, Che B, Chen J, Zhuang Q, Wang Y, Sun J, Zhu D, Zheng P. Reconstruction the feedback regulation of amino acid metabolism to develop a non-auxotrophic L-threonine producing Corynebacterium glutamicum. BIORESOUR BIOPROCESS 2024; 11:43. [PMID: 38664309 PMCID: PMC11045695 DOI: 10.1186/s40643-024-00753-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
L-Threonine is an important feed additive with the third largest market size among the amino acids produced by microbial fermentation. The GRAS (generally regarded as safe) industrial workhorse Corynebacterium glutamicum is an attractive chassis for L-threonine production. However, the present L-threonine production in C. glutamicum cannot meet the requirement of industrialization due to the relatively low production level of L-threonine and the accumulation of large amounts of by-products (such as L-lysine, L-isoleucine, and glycine). Herein, to enhance the L-threonine biosynthesis in C. glutamicum, releasing the aspartate kinase (LysC) and homoserine dehydrogenase (Hom) from feedback inhibition by L-lysine and L-threonine, respectively, and overexpressing four flux-control genes were performed. Next, to reduce the formation of by-products L-lysine and L-isoleucine without the cause of an auxotrophic phenotype, the feedback regulation of dihydrodipicolinate synthase (DapA) and threonine dehydratase (IlvA) was strengthened by replacing the native enzymes with heterologous analogues with more sensitive feedback inhibition by L-lysine and L-isoleucine, respectively. The resulting strain maintained the capability of synthesizing enough amounts of L-lysine and L-isoleucine for cell biomass formation but exhibited almost no extracellular accumulation of these two amino acids. To further enhance L-threonine production and reduce the by-product glycine, L-threonine exporter and homoserine kinase were overexpressed. Finally, the rationally engineered non-auxotrophic strain ZcglT9 produced 67.63 g/L (17.2% higher) L-threonine with a productivity of 1.20 g/L/h (108.0% higher) in fed-batch fermentation, along with significantly reduced by-product accumulation, representing the record for L-threonine production in C. glutamicum. In this study, we developed a strategy of reconstructing the feedback regulation of amino acid metabolism and successfully applied this strategy to de novo construct a non-auxotrophic L-threonine producing C. glutamicum. The main end by-products including L-lysine, L-isoleucine, and glycine were almost eliminated in fed-batch fermentation of the engineered C. glutamicum strain. This strategy can also be used for engineering producing strains for other amino acids and derivatives.
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Affiliation(s)
- Jianhang Liu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
- Shandong Provincial Key Laboratory of Microbial Engineering, School of Bioengineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China
| | - Jiao Liu
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Jiajun Li
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China
- Shandong Provincial Key Laboratory of Microbial Engineering, School of Bioengineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China
| | - Xiaojia Zhao
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Guannan Sun
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Qianqian Qiao
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Tuo Shi
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Bin Che
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Jiuzhou Chen
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Qianqian Zhuang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China
- Shandong Provincial Key Laboratory of Microbial Engineering, School of Bioengineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China
- Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Yu Wang
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Jibin Sun
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Deqiang Zhu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China.
- Shandong Provincial Key Laboratory of Microbial Engineering, School of Bioengineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China.
| | - Ping Zheng
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China.
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Ivanova I, Shen K. Structures and Functions of the Human GATOR1 Complex. Subcell Biochem 2024; 104:269-294. [PMID: 38963491 DOI: 10.1007/978-3-031-58843-3_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Eukaryotic cells coordinate available nutrients with their growth through the mechanistic target of rapamycin complex 1 (mTORC1) pathway, in which numerous evolutionarily conserved protein complexes survey and transmit nutrient inputs toward mTORC1. mTORC1 integrates these inputs and activates downstream anabolic or catabolic programs that are in tune with cellular needs, effectively maintaining metabolic homeostasis. The GAP activity toward Rags-1 (GATOR1) protein complex is a critical negative regulator of the mTORC1 pathway and, in the absence of amino acid inputs, is activated to turn off mTORC1 signaling. GATOR1-mediated inhibition of mTORC1 signaling is tightly regulated by an ensemble of protein complexes that antagonize or promote its activity in response to the cellular nutrient environment. Structural, biochemical, and biophysical studies of the GATOR1 complex and its interactors have advanced our understanding of how it regulates cellular metabolism when amino acids are limited. Here, we review the current research with a focus on GATOR1 structure, its enzymatic mechanism, and the growing group of proteins that regulate its activity. Finally, we discuss the implication of GATOR1 dysregulation in physiology and human diseases.
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Affiliation(s)
- Ilina Ivanova
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA.
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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Lee KT, Liao HS, Hsieh MH. Glutamine Metabolism, Sensing and Signaling in Plants. PLANT & CELL PHYSIOLOGY 2023; 64:1466-1481. [PMID: 37243703 DOI: 10.1093/pcp/pcad054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/23/2023] [Accepted: 05/24/2023] [Indexed: 05/29/2023]
Abstract
Glutamine (Gln) is the first amino acid synthesized in nitrogen (N) assimilation in plants. Gln synthetase (GS), converting glutamate (Glu) and NH4+ into Gln at the expense of ATP, is one of the oldest enzymes in all life domains. Plants have multiple GS isoenzymes that work individually or cooperatively to ensure that the Gln supply is sufficient for plant growth and development under various conditions. Gln is a building block for protein synthesis and an N-donor for the biosynthesis of amino acids, nucleic acids, amino sugars and vitamin B coenzymes. Most reactions using Gln as an N-donor are catalyzed by Gln amidotransferase (GAT) that hydrolyzes Gln to Glu and transfers the amido group of Gln to an acceptor substrate. Several GAT domain-containing proteins of unknown function in the reference plant Arabidopsis thaliana suggest that some metabolic fates of Gln have yet to be identified in plants. In addition to metabolism, Gln signaling has emerged in recent years. The N regulatory protein PII senses Gln to regulate arginine biosynthesis in plants. Gln promotes somatic embryogenesis and shoot organogenesis with unknown mechanisms. Exogenous Gln has been implicated in activating stress and defense responses in plants. Likely, Gln signaling is responsible for some of the new Gln functions in plants.
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Affiliation(s)
- Kim-Teng Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
| | - Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
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7
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Pierson E, De Pol F, Fillet M, Wouters J. A morpheein equilibrium regulates catalysis in phosphoserine phosphatase SerB2 from Mycobacterium tuberculosis. Commun Biol 2023; 6:1024. [PMID: 37817000 PMCID: PMC10564941 DOI: 10.1038/s42003-023-05402-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 09/29/2023] [Indexed: 10/12/2023] Open
Abstract
Mycobacterium tuberculosis phosphoserine phosphatase MtSerB2 is of interest as a new antituberculosis target due to its essential metabolic role in L-serine biosynthesis and effector functions in infected cells. Previous works indicated that MtSerB2 is regulated through an oligomeric transition induced by L-Ser that could serve as a basis for the design of selective allosteric inhibitors. However, the mechanism underlying this transition remains highly elusive due to the lack of experimental structural data. Here we describe a structural, biophysical, and enzymological characterisation of MtSerB2 oligomerisation in the presence and absence of L-Ser. We show that MtSerB2 coexists in dimeric, trimeric, and tetrameric forms of different activity levels interconverting through a conformationally flexible monomeric state, which is not observed in two near-identical mycobacterial orthologs. This morpheein behaviour exhibited by MtSerB2 lays the foundation for future allosteric drug discovery and provides a starting point to the understanding of its peculiar multifunctional moonlighting properties.
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Affiliation(s)
- Elise Pierson
- Laboratoire de Chimie Biologique Structurale (CBS), Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), 5000, Namur, Belgium
| | - Florian De Pol
- Laboratoire de Chimie Biologique Structurale (CBS), Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), 5000, Namur, Belgium
| | - Marianne Fillet
- Laboratory for the Analysis of Medicines (LAM), Center for Interdisciplinary Research on Medicines (CIRM), University of Liège (ULiège), 4000, Liège, Belgium
| | - Johan Wouters
- Laboratoire de Chimie Biologique Structurale (CBS), Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), 5000, Namur, Belgium.
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8
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Liao HS, Chen YJ, Hsieh WY, Li YC, Hsieh MH. Arabidopsis ACT DOMAIN REPEAT9 represses glucose signaling pathways. PLANT PHYSIOLOGY 2023; 192:1532-1547. [PMID: 36843191 PMCID: PMC10231364 DOI: 10.1093/plphys/kiad127] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/06/2023] [Accepted: 02/01/2023] [Indexed: 06/01/2023]
Abstract
Nutrient sensing and signaling are critical for plants to coordinate growth and development in response to nutrient availability. Plant ACT DOMAIN REPEAT (ACR) proteins have been proposed to serve as nutrient sensors, but their functions remain largely unknown. Here, we showed that Arabidopsis (Arabidopsis thaliana) ACR9 might function as a repressor in glucose (Glc) signaling pathways. ACR9 was highly expressed in the leaves, and its expression was downregulated by sugars. Interestingly, the acr9-1 and acr9-2 T-DNA insertion mutants were hypersensitive to Glc during seedling growth, development, and anthocyanin accumulation. Nitrogen deficiency increased the mutants' sensitivity to Glc. The expression of sugar-responsive genes was also significantly enhanced in the acr9 mutants. By contrast, the 35S:ACR9 and 35S:ACR9-GFP overexpression (OE) lines were insensitive to Glc during early seedling development. The Glc signaling pathway is known to interact with the plant hormone abscisic acid (ABA). Notably, the acr9 mutants were also hypersensitive to ABA during early seedling development. The Glc sensor HEXOKINASE1 (HXK1) and the energy sensor SUCROSE NON-FERMENTING1 (SNF1)-RELATED PROTEIN KINASE1 (SnRK1) are key components of the Glc signaling pathways. The acr9-1/hxk1-3 and acr9-1/snrk1 double mutants were no longer hypersensitive to Glc, indicating that functional HXK1 and SnRK1 were required for the acr9-1 mutant to be hypersensitive to Glc. Together, these results suggest that ACR9 is a repressor of the Glc signaling pathway, which may act independently or upstream of the HXK1-SnRK1 signaling module.
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Affiliation(s)
- Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Ying-Jhu Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Wei-Yu Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Chiou Li
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan
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9
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Lee YS, Shiu SH, Grotewold E. Evolution and diversification of the ACT-like domain associated with plant basic helix-loop-helix transcription factors. Proc Natl Acad Sci U S A 2023; 120:e2219469120. [PMID: 37126718 PMCID: PMC10175843 DOI: 10.1073/pnas.2219469120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/21/2023] [Indexed: 05/03/2023] Open
Abstract
Basic helix-loop-helix (bHLH) proteins are one of the largest families of transcription factor (TF) in eukaryotes, and ~30% of all flowering plants' bHLH TFs contain the aspartate kinase, chorismate mutase, and TyrA (ACT)-like domain at variable distances C-terminal from the bHLH. However, the evolutionary history and functional consequences of the bHLH/ACT-like domain association remain unknown. Here, we show that this domain association is unique to the plantae kingdom with green algae (chlorophytes) harboring a small number of bHLH genes with variable frequency of ACT-like domain's presence. bHLH-associated ACT-like domains form a monophyletic group, indicating a common origin. Indeed, phylogenetic analysis results suggest that the association of ACT-like and bHLH domains occurred early in Plantae by recruitment of an ACT-like domain in a common ancestor with widely distributed ACT DOMAIN REPEAT (ACR) genes by an ancestral bHLH gene. We determined the functional significance of this association by showing that Chlamydomonas reinhardtii ACT-like domains mediate homodimer formation and negatively affect DNA binding of the associated bHLH domains. We show that, while ACT-like domains have experienced faster selection than the associated bHLH domain, their rates of evolution are strongly and positively correlated, suggesting that the evolution of the ACT-like domains was constrained by the bHLH domains. This study proposes an evolutionary trajectory for the association of ACT-like and bHLH domains with the experimental characterization of the functional consequence in the regulation of plant-specific processes, highlighting the impacts of functional domain coevolution.
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Affiliation(s)
- Yun Sun Lee
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI48824
| | - Shin-Han Shiu
- Department of Plant Biology, Michigan State University, East Lansing, MI48824
- Department of Computational Mathematics, Science, and Engineering, Michigan State University, East Lansing, MI48824
| | - Erich Grotewold
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI48824
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Vedel IM, Prestel A, Zhang Z, Skawinska NT, Stark H, Harris P, Kragelund BB, Peters GHJ. Structural characterization of human tryptophan hydroxylase 2 reveals that L-Phe is superior to L-Trp as the regulatory domain ligand. Structure 2023:S0969-2126(23)00127-2. [PMID: 37119821 DOI: 10.1016/j.str.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 03/03/2023] [Accepted: 04/04/2023] [Indexed: 05/01/2023]
Abstract
Tryptophan hydroxylase 2 (TPH2) catalyzes the rate-limiting step in serotonin biosynthesis in the brain. Consequently, regulation of TPH2 is relevant for serotonin-related diseases, yet the regulatory mechanism of TPH2 is poorly understood and structural and dynamical insights are missing. We use NMR spectroscopy to determine the structure of a 47 N-terminally truncated variant of the regulatory domain (RD) dimer of human TPH2 in complex with L-Phe, and show that L-Phe is the superior RD ligand compared with the natural substrate, L-Trp. Using cryo-EM, we obtain a low-resolution structure of a similarly truncated variant of the complete tetrameric enzyme with dimerized RDs. The cryo-EM two-dimensional (2D) class averages additionally indicate that the RDs are dynamic in the tetramer and likely exist in a monomer-dimer equilibrium. Our results provide structural information on the RD as an isolated domain and in the TPH2 tetramer, which will facilitate future elucidation of TPH2's regulatory mechanism.
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Affiliation(s)
- Ida M Vedel
- Department of Chemistry, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
| | - Andreas Prestel
- Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark
| | - Zhenwei Zhang
- Department of Structural Dynamics, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Natalia T Skawinska
- Department of Chemistry, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
| | - Holger Stark
- Department of Structural Dynamics, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Pernille Harris
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Birthe B Kragelund
- Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark.
| | - Günther H J Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark.
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11
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Bai Y, Jiao W, Vörster J, Parker EJ. Conformational interdomain flexibility in a bacterial α-isopropylmalate synthase is necessary for leucine biosynthesis. J Biol Chem 2022; 299:102789. [PMID: 36509144 PMCID: PMC9860122 DOI: 10.1016/j.jbc.2022.102789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
α-Isopropylmalate synthase (IPMS) catalyzes the first step in leucine (Leu) biosynthesis and is allosterically regulated by the pathway end product, Leu. IPMS is a dimeric enzyme with each chain consisting of catalytic, accessory, and regulatory domains, with the accessory and regulatory domains of each chain sitting adjacent to the catalytic domain of the other chain. The IPMS crystal structure shows significant asymmetry because of different relative domain conformations in each chain. Owing to the challenges posed by the dynamic and asymmetric structures of IPMS enzymes, the molecular details of their catalytic and allosteric mechanisms are not fully understood. In this study, we have investigated the allosteric feedback mechanism of the IPMS enzyme from the bacterium that causes meningitis, Neisseria meningitidis (NmeIPMS). By combining molecular dynamics simulations with small-angle X-ray scattering, mutagenesis, and heterodimer generation, we demonstrate that Leu-bound NmeIPMS is in a rigid conformational state stabilized by asymmetric interdomain polar interactions. Furthermore, we found removing these polar interactions by mutagenesis impaired the allosteric response without compromising Leu binding. Our results suggest that the allosteric inhibition of NmeIPMS is achieved by restricting the flexibility of the accessory and regulatory domains, demonstrating that significant conformational flexibility is required for catalysis.
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Affiliation(s)
- Yu Bai
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Wanting Jiao
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Jan Vörster
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Emily J. Parker
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand,For correspondence: Emily J. Parker
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12
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Meng D, Yang Q, Jeong MH, Curukovic A, Tiwary S, Melick CH, Lama-Sherpa TD, Wang H, Huerta-Rosario M, Urquhart G, Zacharias LG, Lewis C, DeBerardinis RJ, Jewell JL. SNAT7 regulates mTORC1 via macropinocytosis. Proc Natl Acad Sci U S A 2022; 119:e2123261119. [PMID: 35561222 PMCID: PMC9171778 DOI: 10.1073/pnas.2123261119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 03/13/2022] [Indexed: 11/30/2022] Open
Abstract
Mammalian target of rapamycin complex 1 (mTORC1) senses amino acids to control cell growth, metabolism, and autophagy. Some amino acids signal to mTORC1 through the Rag GTPase, whereas glutamine and asparagine activate mTORC1 through a Rag GTPase-independent pathway. Here, we show that the lysosomal glutamine and asparagine transporter SNAT7 activates mTORC1 after extracellular protein, such as albumin, is macropinocytosed. The N terminus of SNAT7 forms nutrient-sensitive interaction with mTORC1 and regulates mTORC1 activation independently of the Rag GTPases. Depletion of SNAT7 inhibits albumin-induced mTORC1 lysosomal localization and subsequent activation. Moreover, SNAT7 is essential to sustain KRAS-driven pancreatic cancer cell growth through mTORC1. Thus, SNAT7 links glutamine and asparagine signaling from extracellular protein to mTORC1 independently of the Rag GTPases and is required for macropinocytosis-mediated mTORC1 activation and pancreatic cancer cell growth.
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Affiliation(s)
- Delong Meng
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Qianmei Yang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Mi-Hyeon Jeong
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Adna Curukovic
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Shweta Tiwary
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Chase H. Melick
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Tshering D. Lama-Sherpa
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Huanyu Wang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Mariela Huerta-Rosario
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Greg Urquhart
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Lauren G. Zacharias
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Cheryl Lewis
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Ralph J. DeBerardinis
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jenna L. Jewell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
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13
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Amino Acid Signaling for TOR in Eukaryotes: Sensors, Transducers, and a Sustainable Agricultural fuTORe. Biomolecules 2022; 12:biom12030387. [PMID: 35327579 PMCID: PMC8945916 DOI: 10.3390/biom12030387] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells monitor and regulate metabolism through the atypical protein kinase target of rapamycin (TOR) regulatory hub. TOR is activated by amino acids in animals and fungi through molecular signaling pathways that have been extensively defined in the past ten years. Very recently, several studies revealed that TOR is also acutely responsive to amino acid metabolism in plants, but the mechanisms of amino acid sensing are not yet established. In this review, we summarize these discoveries, emphasizing the diversity of amino acid sensors in human cells and highlighting pathways that are indirectly sensitive to amino acids, i.e., how TOR monitors changes in amino acid availability without a bona fide amino acid sensor. We then discuss the relevance of these model discoveries to plant biology. As plants can synthesize all proteinogenic amino acids from inorganic precursors, we focus on the possibility that TOR senses both organic metabolites and inorganic nutrients. We conclude that an evolutionary perspective on nutrient sensing by TOR benefits both agricultural and biomedical science, contributing to ongoing efforts to generate crops for a sustainable agricultural future.
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14
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High-level Production of Isoleucine and Fusel alcohol by expression of the Feedback Inhibition-insensitive Threonine deaminase in Saccharomyces cerevisiae. Appl Environ Microbiol 2022; 88:e0213021. [PMID: 35020456 PMCID: PMC8904041 DOI: 10.1128/aem.02130-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A variety of the yeast Saccharomyces cerevisiae with intracellular accumulation of isoleucine (Ile) would be a promising strain for developing a distinct kind of sake, a traditional Japanese alcoholic beverage, because Ile-derived volatile compounds have a great impact on the flavor and taste of fermented foods. In this study, we isolated an Ile-accumulating mutant (strain K9-I48) derived from a diploid sake yeast of S. cerevisiae by conventional mutagenesis. Strain K9-I48 carries a novel mutation in the ILV1 gene encoding the His480Tyr variant of threonine deaminase (TD). Interestingly, the TD activity of the His480Tyr variant was markedly insensitive to feedback inhibition by Ile, but was not upregulated by valine, leading to intracellular accumulation of Ile and extracellular overproduction of 2-methyl-1-butanol, a fusel alcohol derived from Ile, in yeast cells. The present study demonstrated for the first time that the conserved histidine residue located in a linker region between two regulatory domains is involved in allosteric regulation of TD. Moreover, sake brewed with strain K9-I48 contained 2 to 3 times more 2-methyl-1-butanol and 2-methylbutyl acetate than sake brewed with the parent strain. These findings are valuable for the engineering of TD to increase the productivity of Ile and its derived fusel alcohols. IMPORTANCE Fruit-like flavors of isoleucine-derived volatile compounds, 2-methyl-1-butanol (2MB) and its acetate ester, contribute to a variety of the flavors and tastes of alcoholic beverages. Besides its value as aroma components in foods and cosmetics, 2MB has attracted significant attention as second-generation biofuels. Threonine deaminase (TD) catalyzes the first step in isoleucine biosynthesis and its activity is subject to feedback inhibition by isoleucine. Here, we isolated an isoleucine-accumulating sake yeast mutant and identified a mutant gene encoding a novel variant of TD. The variant TD exhibited much less sensitivity to isoleucine, leading to higher production of 2MB as well as isoleucine than the wild-type TD. Furthermore, sake brewed with a mutant yeast expressing the variant TD contained more 2MB and its acetate ester than that brewed with the parent strain. These findings will contribute to the development of superior industrial yeast strains for high-level production of isoleucine and its related fusel alcohols.
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15
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Bai Y, Parker EJ. Reciprocal allostery arising from a bienzyme assembly controls aromatic amino acid biosynthesis in Prevotella nigrescens. J Biol Chem 2021; 297:101038. [PMID: 34343567 PMCID: PMC8408635 DOI: 10.1016/j.jbc.2021.101038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 11/16/2022] Open
Abstract
Modular protein assembly has been widely reported as a mechanism for constructing allosteric machinery. Recently, a distinctive allosteric system has been identified in a bienzyme assembly comprising a 3-deoxy-d-arabino heptulosonate-7-phosphate synthase (DAH7PS) and chorismate mutase (CM). These enzymes catalyze the first and branch point reactions of aromatic amino acid biosynthesis in the bacterium Prevotella nigrescens (PniDAH7PS), respectively. The interactions between these two distinct catalytic domains support functional interreliance within this bifunctional enzyme. The binding of prephenate, the product of CM-catalyzed reaction, to the CM domain is associated with a striking rearrangement of overall protein conformation that alters the interdomain interactions and allosterically inhibits the DAH7PS activity. Here, we have further investigated the complex allosteric communication demonstrated by this bifunctional enzyme. We observed allosteric activation of CM activity in the presence of all DAH7PS substrates. Using small-angle X-ray scattering (SAXS) experiments, we show that changes in overall protein conformations and dynamics are associated with the presence of different DAH7PS substrates and the allosteric inhibitor prephenate. Furthermore, we have identified an extended interhelix loop located in CM domain, loopC320-F333, as a crucial segment for the interdomain structural and catalytic communications. Our results suggest that the dual-function enzyme PniDAH7PS contains a reciprocal allosteric system between the two enzymatic moieties as a result of this bidirectional interdomain communication. This arrangement allows for a complex feedback and feedforward system for control of pathway flux by connecting the initiation and branch point of aromatic amino acid biosynthesis.
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Affiliation(s)
- Yu Bai
- Maurice Wilkins Centre, Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Emily J Parker
- Maurice Wilkins Centre, Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand.
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16
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3D architecture and structural flexibility revealed in the subfamily of large glutamate dehydrogenases by a mycobacterial enzyme. Commun Biol 2021; 4:684. [PMID: 34083757 PMCID: PMC8175468 DOI: 10.1038/s42003-021-02222-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 05/14/2021] [Indexed: 11/16/2022] Open
Abstract
Glutamate dehydrogenases (GDHs) are widespread metabolic enzymes that play key roles in nitrogen homeostasis. Large glutamate dehydrogenases composed of 180 kDa subunits (L-GDHs180) contain long N- and C-terminal segments flanking the catalytic core. Despite the relevance of L-GDHs180 in bacterial physiology, the lack of structural data for these enzymes has limited the progress of functional studies. Here we show that the mycobacterial L-GDH180 (mL-GDH180) adopts a quaternary structure that is radically different from that of related low molecular weight enzymes. Intersubunit contacts in mL-GDH180 involve a C-terminal domain that we propose as a new fold and a flexible N-terminal segment comprising ACT-like and PAS-type domains that could act as metabolic sensors for allosteric regulation. These findings uncover unique aspects of the structure-function relationship in the subfamily of L-GDHs. Lázaro et. al. report the first 3D structure of a large glutamate dehydrogenase (L-GDH), the one corresponding to the Mycobacterium smegmatis enzyme composed of 180 kDa subunits (mL-GDH180), obtained by X-ray crystallography and cryo-electron microscopy. This structure reveals that mL-GDH180 assembles as tetramers with the N- and C-terminal domains being involved in inter-subunit contacts and unveils unique features of the subfamily of L-GDHs.
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17
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Arturo EC, Merkel GW, Hansen MR, Lisowski S, Almeida D, Gupta K, Jaffe EK. Manipulation of a cation-π sandwich reveals conformational flexibility in phenylalanine hydroxylase. Biochimie 2021; 183:63-77. [PMID: 33221376 PMCID: PMC9856217 DOI: 10.1016/j.biochi.2020.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/04/2020] [Accepted: 11/10/2020] [Indexed: 01/24/2023]
Abstract
Phenylalanine hydroxylase (PAH) is an allosteric enzyme that maintains phenylalanine (Phe) below neurotoxic levels; its failure results in phenylketonuria, an inborn error of amino acid metabolism. Wild type (WT) PAH equilibrates among resting-state (RS-PAH) and activated (A-PAH) conformations, whose equilibrium position depends upon allosteric Phe binding. The RS-PAH conformation of WT rat PAH (rPAH) contains a cation-π sandwich involving Phe80 that cannot exist in the A-PAH conformation. Phe80 variants F80A, F80D, F80L, and F80R were prepared and evaluated using native PAGE, size exclusion chromatography, ion exchange behavior, intrinsic protein fluorescence, enzyme kinetics, and limited proteolysis, each as a function of [Phe]. Like WT rPAH, F80A and F80D show allosteric activation by Phe while F80L and F80R are constitutively active. Maximal activity of all variants suggests relief of a rate-determining conformational change. Limited proteolysis of WT rPAH (minus Phe) reveals facile cleavage within a 4-helix bundle that is buried in the RS-PAH tetramer interface, reflecting dynamic dissociation of that tetramer. This cleavage is not seen for the Phe80 variants, which all show proteolytic hypersensitivity in a linker that repositions during the RS-PAH to A-PAH interchange. Hypersensitivity is corrected by addition of Phe such that all variants become like WT rPAH and achieve the A-PAH conformation. Thus, manipulation of Phe80 perturbs the conformational space sampled by PAH, increasing sampling of on-pathway intermediates in the RS-PAH and A-PAH interchange. The behavior of the Phe80 variants mimics that of disease-associated R68S and suggests a molecular basis for proteolytic susceptibility in PKU-associated human PAH variants.
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Affiliation(s)
- Emilia C. Arturo
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111,Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102
| | - George W. Merkel
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Michael R. Hansen
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Sophia Lisowski
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Deeanne Almeida
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Kushol Gupta
- Department pf Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Eileen K. Jaffe
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111,To whom correspondence should be addressed: Eileen K. Jaffe: Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA 19111; ; Tel.(215) 728-3695; Fax. (215) 728-2412
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18
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Bezem MT, Johannessen FG, Kråkenes TA, Sailor MJ, Martinez A. Relevance of Electrostatics for the Interaction of Tyrosine Hydroxylase with Porous Silicon Nanoparticles. Mol Pharm 2021; 18:976-985. [PMID: 33417459 PMCID: PMC7927144 DOI: 10.1021/acs.molpharmaceut.0c00960] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Tyrosine hydroxylase (TH) is the
enzyme catalyzing the rate-limiting
step in the synthesis of dopamine in the brain. Developing enzyme
replacement therapies using TH could therefore be beneficial to patient
groups with dopamine deficiency, and the use of nanocarriers that
cross the blood–brain barrier seems advantageous for this purpose.
Nanocarriers may also help to maintain the structure and function
of TH, which is complex and unstable. Understanding how TH may interact
with a nanocarrier is therefore crucial for the investigation of such
therapeutic applications. This work describes the interaction of TH
with porous silicon nanoparticles (pSiNPs), chosen since they have
been shown to deliver other macromolecular therapeutics successfully
to the brain. Size distributions obtained by dynamic light scattering
show a size increase of pSiNPs upon addition of TH and the changes
observed at the surface of pSiNPs by transmission electron microscopy
also indicated TH binding at pH 7. As pSiNPs are negatively charged,
we also investigated the binding at pH 6, which makes TH less negatively
charged than at pH 7. However, as seen by thioflavin-T fluorescence,
TH aggregated at this more acidic pH. TH activity was unaffected by
the binding to pSiNPs most probably because the active site stays
available for catalysis, in agreement with calculations of the surface
electrostatic potential pointing to the most positively charged regulatory
domains in the tetramer as the interacting regions. These results
reveal pSiNPs as a promising delivery device of enzymatically active
TH to increase local dopamine synthesis.
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Affiliation(s)
- Maria T Bezem
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, Bergen 5009, Norway
| | - Fredrik G Johannessen
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, Bergen 5009, Norway
| | - Trond-André Kråkenes
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, Bergen 5009, Norway
| | - Michael J Sailor
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, Bergen 5009, Norway
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19
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Diverse allosteric componentry and mechanisms control entry into aromatic metabolite biosynthesis. Curr Opin Struct Biol 2020; 65:159-167. [DOI: 10.1016/j.sbi.2020.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/19/2020] [Accepted: 06/24/2020] [Indexed: 02/01/2023]
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20
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Harjes E, Jameson GB, Tu YH, Burr N, Loo TS, Goroncy AK, Edwards PJB, Harjes S, Munro B, Göbl C, Sattlegger E, Norris GE. Experimentally based structural model of Yih1 provides insight into its function in controlling the key translational regulator Gcn2. FEBS Lett 2020; 595:324-340. [PMID: 33156522 DOI: 10.1002/1873-3468.13990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/21/2020] [Accepted: 11/02/2020] [Indexed: 12/15/2022]
Abstract
Yeast impact homolog 1 (Yih1), or IMPACT in mammals, is part of a conserved regulatory module controlling the activity of General Control Nonderepressible 2 (Gcn2), a protein kinase that regulates protein synthesis. Yih1/IMPACT is implicated not only in many essential cellular processes, such as neuronal development, immune system regulation and the cell cycle, but also in cancer. Gcn2 must bind to Gcn1 in order to impair the initiation of protein translation. Yih1 hinders this key Gcn1-Gcn2 interaction by binding to Gcn1, thus preventing Gcn2-mediated inhibition of protein synthesis. Here, we solved the structures of the two domains of Saccharomyces cerevisiae Yih1 separately using Nuclear Magnetic Resonance and determined the relative positions of the two domains using a range of biophysical methods. Our findings support a compact structural model of Yih1 in which the residues required for Gcn1 binding are buried in the interface. This model strongly implies that Yih1 undergoes a large conformational rearrangement from a latent closed state to a primed open state to bind Gcn1. Our study provides structural insight into the interactions of Yih1 with partner molecules.
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Affiliation(s)
- Elena Harjes
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand
| | - Geoffrey B Jameson
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand
| | - Yi-Hsuan Tu
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Natalie Burr
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Trevor S Loo
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Alexander K Goroncy
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Patrick J B Edwards
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Stefan Harjes
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Ben Munro
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Christoph Göbl
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Evelyn Sattlegger
- Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand.,School of Natural and Computational Sciences, Massey University, Auckland, New Zealand
| | - Gillian E Norris
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand
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21
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Zeytuni N, Dickey SW, Hu J, Chou HT, Worrall LJ, Alexander JAN, Carlson ML, Nosella M, Duong F, Yu Z, Otto M, Strynadka NCJ. Structural insight into the Staphylococcus aureus ATP-driven exporter of virulent peptide toxins. SCIENCE ADVANCES 2020; 6:eabb8219. [PMID: 32998902 PMCID: PMC7527219 DOI: 10.1126/sciadv.abb8219] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/14/2020] [Indexed: 06/06/2023]
Abstract
Staphylococcus aureus is a major human pathogen that has acquired alarming broad-spectrum antibiotic resistance. One group of secreted toxins with key roles during infection is the phenol-soluble modulins (PSMs). PSMs are amphipathic, membrane-destructive cytolytic peptides that are exported to the host-cell environment by a designated adenosine 5'-triphosphate (ATP)-binding cassette (ABC) transporter, the PSM transporter (PmtABCD). Here, we demonstrate that the minimal Pmt unit necessary for PSM export is PmtCD and provide its first atomic characterization by single-particle cryo-EM and x-ray crystallography. We have captured the transporter in the ATP-bound state at near atomic resolution, revealing a type II ABC exporter fold, with an additional cytosolic domain. Comparison to a lower-resolution nucleotide-free map displaying an "open" conformation and putative hydrophobic inner chamber of a size able to accommodate the binding of two PSM peptides provides mechanistic insight and sets the foundation for therapeutic design.
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Affiliation(s)
- N. Zeytuni
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - S. W. Dickey
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - J. Hu
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - H. T. Chou
- CryoEM Shared Resources, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - L. J. Worrall
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
- High Resolution Macromolecular Cryo-Electron Microscopy facility, University of British Columbia, Vancouver, V6T 1Z3, BC, Canada
| | - J. A. N. Alexander
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - M. L. Carlson
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - M. Nosella
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - F. Duong
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Z. Yu
- CryoEM Shared Resources, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - M. Otto
- CryoEM Shared Resources, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - N. C. J. Strynadka
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
- High Resolution Macromolecular Cryo-Electron Microscopy facility, University of British Columbia, Vancouver, V6T 1Z3, BC, Canada
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22
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Lonhienne T, Low YS, Garcia MD, Croll T, Gao Y, Wang Q, Brillault L, Williams CM, Fraser JA, McGeary RP, West NP, Landsberg MJ, Rao Z, Schenk G, Guddat LW. Structures of fungal and plant acetohydroxyacid synthases. Nature 2020; 586:317-321. [PMID: 32640464 DOI: 10.1038/s41586-020-2514-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 06/01/2020] [Indexed: 02/06/2023]
Abstract
Acetohydroxyacid synthase (AHAS), also known as acetolactate synthase, is a flavin adenine dinucleotide-, thiamine diphosphate- and magnesium-dependent enzyme that catalyses the first step in the biosynthesis of branched-chain amino acids1. It is the target for more than 50 commercial herbicides2. AHAS requires both catalytic and regulatory subunits for maximal activity and functionality. Here we describe structures of the hexadecameric AHAS complexes of Saccharomyces cerevisiae and dodecameric AHAS complexes of Arabidopsis thaliana. We found that the regulatory subunits of these AHAS complexes form a core to which the catalytic subunit dimers are attached, adopting the shape of a Maltese cross. The structures show how the catalytic and regulatory subunits communicate with each other to provide a pathway for activation and for feedback inhibition by branched-chain amino acids. We also show that the AHAS complex of Mycobacterium tuberculosis adopts a similar structure, thus demonstrating that the overall AHAS architecture is conserved across kingdoms.
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Affiliation(s)
- Thierry Lonhienne
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.
| | - Yu Shang Low
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Mario D Garcia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Tristan Croll
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Yan Gao
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Quan Wang
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Lou Brillault
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - James A Fraser
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Ross P McGeary
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Nicholas P West
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Michael J Landsberg
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Zihe Rao
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,State Key Laboratory of Medicinal Chemical Biology, College of Life Science, Nankai University, Tianjin, China.,Laboratory of Structural Biology, Tsinghua University, Beijing, China
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Luke W Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.
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23
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Xie J, Lai L. Protein topology and allostery. Curr Opin Struct Biol 2020; 62:158-165. [DOI: 10.1016/j.sbi.2020.01.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 01/12/2020] [Accepted: 01/16/2020] [Indexed: 01/07/2023]
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24
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The lineage and diversity of putative amino acid sensor ACR proteins in plants. Amino Acids 2020; 52:649-666. [PMID: 32306102 DOI: 10.1007/s00726-020-02844-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 04/11/2020] [Indexed: 10/24/2022]
Abstract
Amino acid metabolic enzymes often contain a regulatory ACT domain, named for aspartate kinase, chorismate mutase, and TyrA (prephenate dehydrogenase). Arabidopsis encodes 12 putative amino acid sensor ACT repeat (ACR) proteins, all containing ACT repeats but no identifiable catalytic domain. Arabidopsis ACRs comprise three groups based on domain composition and sequence: group I and II ACRs contain four ACTs each, and group III ACRs contain two ACTs. Previously, all three groups had been documented only in Arabidopsis. Here, we extended this to algae and land plants, showing that all three groups of ACRs are present in most, if not all, land plants, whereas among algal ACRs, although quite diverse, only group III is conserved. The appearance of canonical group I and II ACRs thus accompanied the evolution of plants from living in water to living on land. Alignment of ACTs from plant ACRs revealed a conserved motif, DRPGLL, at the putative ligand-binding site. Notably, the unique features of the DRPGLL motifs in each ACT domain are conserved in ACRs from algae to land plants. The conservation of plant ACRs is reminiscent of that of human cellular arginine sensor for mTORC1 (CASTOR1), a member of a small protein family highly conserved in animals. CASTOR proteins also have four ACT domains, although the sequence identities between ACRs and CASTORs are very low. Thus, plant ACRs and animal CASTORs may have adapted the regulatory ACT domains from a more ancient metabolic enzyme, and then evolved independently.
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25
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Shabalin IG, Gritsunov A, Hou J, Sławek J, Miks CD, Cooper DR, Minor W, Christendat D. Structural and biochemical analysis of Bacillus anthracis prephenate dehydrogenase reveals an unusual mode of inhibition by tyrosine via the ACT domain. FEBS J 2019; 287:2235-2255. [PMID: 31750992 DOI: 10.1111/febs.15150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/05/2019] [Accepted: 11/19/2019] [Indexed: 01/19/2023]
Abstract
Tyrosine biosynthesis via the shikimate pathway is absent in humans and other animals, making it an attractive target for next-generation antibiotics, which is increasingly important due to the looming proliferation of multidrug-resistant pathogens. Tyrosine biosynthesis is also of commercial importance for the environmentally friendly production of numerous compounds, such as pharmaceuticals, opioids, aromatic polymers, and petrochemical aromatics. Prephenate dehydrogenase (PDH) catalyzes the penultimate step of tyrosine biosynthesis in bacteria: the oxidative decarboxylation of prephenate to 4-hydroxyphenylpyruvate. The majority of PDHs are competitively inhibited by tyrosine and consist of a nucleotide-binding domain and a dimerization domain. Certain PDHs, including several from pathogens on the World Health Organization priority list of antibiotic-resistant bacteria, possess an additional ACT domain. However, biochemical and structural knowledge was lacking for these enzymes. In this study, we successfully established a recombinant protein expression system for PDH from Bacillus anthracis (BaPDH), the causative agent of anthrax, and determined the structure of a BaPDH ternary complex with NAD+ and tyrosine, a binary complex with tyrosine, and a structure of an isolated ACT domain dimer. We also conducted detailed kinetic and biophysical analyses of the enzyme. We show that BaPDH is allosterically regulated by tyrosine binding to the ACT domains, resulting in an asymmetric conformation of the BaDPH dimer that sterically prevents prephenate binding to either active site. The presented mode of allosteric inhibition is unique compared to both the competitive inhibition established for other PDHs and to the allosteric mechanisms for other ACT-containing enzymes. This study provides new structural and mechanistic insights that advance our understanding of tyrosine biosynthesis in bacteria. ENZYMES: Prephenate dehydrogenase from Bacillus anthracis (PDH): EC database ID: 1.3.1.12. DATABASES: Coordinates and structure factors have been deposited in the Protein Data Bank (PDB) with accession numbers PDB ID: 6U60 (BaPDH complex with NAD+ and tyrosine), PDB ID: 5UYY (BaPDH complex with tyrosine), and PDB ID: 5V0S (BaPDH isolated ACT domain dimer). The diffraction images are available at http://proteindiffraction.org with DOIs: https://doi.org/10.18430/M35USC, https://doi.org/10.18430/M35UYY, and https://doi.org/10.18430/M35V0S.
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Affiliation(s)
- Ivan G Shabalin
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.,Center for Structural Genomics of Infectious Diseases (CSGID), Charlottesville, VA, USA
| | - Artyom Gritsunov
- Department of Cell and Systems Biology, University of Toronto, ON, Canada
| | - Jing Hou
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.,Center for Structural Genomics of Infectious Diseases (CSGID), Charlottesville, VA, USA
| | - Joanna Sławek
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.,Center for Structural Genomics of Infectious Diseases (CSGID), Charlottesville, VA, USA.,Faculty of Chemistry, Jagiellonian University, Krakow, Poland
| | - Charles D Miks
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - David R Cooper
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.,Center for Structural Genomics of Infectious Diseases (CSGID), Charlottesville, VA, USA
| | - Wladek Minor
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.,Center for Structural Genomics of Infectious Diseases (CSGID), Charlottesville, VA, USA
| | - Dinesh Christendat
- Department of Cell and Systems Biology, University of Toronto, ON, Canada
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26
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Eisa A, Bölter B, Schwenkert S. The ACT domain in chloroplast precursor-phosphorylating STY kinases binds metabolites and allosterically regulates kinase activity. J Biol Chem 2019; 294:17278-17288. [PMID: 31594863 DOI: 10.1074/jbc.ra119.010298] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/03/2019] [Indexed: 11/06/2022] Open
Abstract
Protein import of nucleus-encoded proteins into plant chloroplasts is a highly regulated process, requiring fine-tuning mechanisms especially during chloroplast differentiation. One way of altering import efficiency is phosphorylation of chloroplast transit peptides in the cytosol. We recently investigated the role of three serine/threonine/tyrosine (STY) kinases, STY8, STY17, and STY46, in precursor phosphorylation. These three kinases have a high degree of similarity and harbor a conserved aspartate kinase-chorismate mutase-tyrA (prephenate dehydrogenase) (ACT) domain upstream of the kinase domain. The ACT domain is a widely distributed structural motif known to be important for allosteric regulation of many enzymes. In this work, using biochemical and biophysical techniques in vitro and in planta, including kinase assays, microscale thermophoresis, size exclusion chromatography, as well as site-directed mutagenesis approaches, we show that the ACT domain regulates autophosphorylation and substrate phosphorylation of the STY kinases. We found that isoleucine and S-adenosylmethionine bind to the ACT domain, negatively influencing its autophosphorylation ability. Moreover, we investigated the role of the ACT domain in planta and confirmed its involvement in chloroplast differentiation in vivo Our results provide detailed insights into the regulation of enzyme activity by ACT domains and establish that it has a role in binding amino acid ligands during chloroplast biogenesis.
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Affiliation(s)
- Ahmed Eisa
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany
| | - Bettina Bölter
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany
| | - Serena Schwenkert
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany
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27
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Gorman SD, Boehr DD. Energy and Enzyme Activity Landscapes of Yeast Chorismate Mutase at Cellular Concentrations of Allosteric Effectors. Biochemistry 2019; 58:4058-4069. [DOI: 10.1021/acs.biochem.9b00721] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Scott D. Gorman
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - David D. Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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28
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Arturo EC, Gupta K, Hansen MR, Borne E, Jaffe EK. Biophysical characterization of full-length human phenylalanine hydroxylase provides a deeper understanding of its quaternary structure equilibrium. J Biol Chem 2019; 294:10131-10145. [PMID: 31076506 PMCID: PMC6664189 DOI: 10.1074/jbc.ra119.008294] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/09/2019] [Indexed: 11/06/2022] Open
Abstract
Dysfunction of human phenylalanine hydroxylase (hPAH, EC 1.14.16.1) is the primary cause of phenylketonuria, the most common inborn error of amino acid metabolism. The dynamic domain rearrangements of this multimeric protein have thwarted structural study of the full-length form for decades, until now. In this study, a tractable C29S variant of hPAH (C29S) yielded a 3.06 Å resolution crystal structure of the tetrameric resting-state conformation. We used size-exclusion chromatography in line with small-angle X-ray scattering (SEC-SAXS) to analyze the full-length hPAH solution structure both in the presence and absence of Phe, which serves as both substrate and allosteric activators. Allosteric Phe binding favors accumulation of an activated PAH tetramer conformation, which is biophysically distinct in solution. Protein characterization with enzyme kinetics and intrinsic fluorescence revealed that the C29S variant and hPAH are otherwise equivalent in their response to Phe, further supported by their behavior on various chromatography resins and by analytical ultracentrifugation. Modeling of resting-state and activated forms of C29S against SAXS data with available structural data created and evaluated several new models for the transition between the architecturally distinct conformations of PAH and highlighted unique intra- and inter-subunit interactions. Three best-fitting alternative models all placed the allosteric Phe-binding module 8-10 Å farther from the tetramer center than do all previous models. The structural insights into allosteric activation of hPAH reported here may help inform ongoing efforts to treat phenylketonuria with novel therapeutic approaches.
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Affiliation(s)
- Emilia C Arturo
- From the Molecular Therapeutics Program, Fox Chase Cancer Center, Temple University Health Systems, Philadelphia, Pennsylvania 19111
- the Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, and
| | - Kushol Gupta
- the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Michael R Hansen
- From the Molecular Therapeutics Program, Fox Chase Cancer Center, Temple University Health Systems, Philadelphia, Pennsylvania 19111
| | - Elias Borne
- From the Molecular Therapeutics Program, Fox Chase Cancer Center, Temple University Health Systems, Philadelphia, Pennsylvania 19111
| | - Eileen K Jaffe
- From the Molecular Therapeutics Program, Fox Chase Cancer Center, Temple University Health Systems, Philadelphia, Pennsylvania 19111,
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29
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Bansal A, Karanth NM, Demeler B, Schindelin H, Sarma SP. Crystallographic Structures of IlvN·Val/Ile Complexes: Conformational Selectivity for Feedback Inhibition of Aceto Hydroxy Acid Synthases. Biochemistry 2019; 58:1992-2008. [PMID: 30887800 PMCID: PMC6668035 DOI: 10.1021/acs.biochem.9b00050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Conformational factors that predicate selectivity for valine or isoleucine binding to IlvN leading to the regulation of aceto hydroxy acid synthase I (AHAS I) of Escherichia coli have been determined for the first time from high-resolution (1.9-2.43 Å) crystal structures of IlvN·Val and IlvN·Ile complexes. The valine and isoleucine ligand binding pockets are located at the dimer interface. In the IlvN·Ile complex, among residues in the binding pocket, the side chain of Cys43 is 2-fold disordered (χ1 angles of gauche- and trans). Only one conformation can be observed for the identical residue in the IlvN·Val complexes. In a reversal, the side chain of His53, located at the surface of the protein, exhibits two conformations in the IlvN·Val complex. The concerted conformational switch in the side chains of Cys43 and His53 may play an important role in the regulation of the AHAS I holoenzyme activity. A significant result is the establishment of the subunit composition in the AHAS I holoenzyme by analytical ultracentrifugation. Solution nuclear magnetic resonance and analytical ultracentrifugation experiments have also provided important insights into the hydrodynamic properties of IlvN in the ligand-free and -bound states. The structural and biophysical data unequivocally establish the molecular basis for differential binding of the ligands to IlvN and a rationale for the resistance of IlvM to feedback inhibition by the branched-chain amino acids.
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Affiliation(s)
- Akanksha Bansal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - N. Megha Karanth
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Borries Demeler
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, Mailcode 7760, 7703 Floyd Curl Drive, San Antonio, Texas 78229-3900, United States
| | - Hermann Schindelin
- Rudolf Virchow Centre for Experimental Biomedicine, Institute of Structural Biology, University of Wuerzburg, Josef-Schneider-Strasse 2, D-97080 Wuerzburg, Germany
| | - Siddhartha P. Sarma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
- NMR Research Center, Indian Institute of Science, Bangalore, Karnataka 560012, India
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30
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Khan CA, Meisburger SP, Ando N, Fitzpatrick PF. The phenylketonuria-associated substitution R68S converts phenylalanine hydroxylase to a constitutively active enzyme but reduces its stability. J Biol Chem 2019; 294:4359-4367. [PMID: 30674554 DOI: 10.1074/jbc.ra118.006477] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/15/2019] [Indexed: 11/06/2022] Open
Abstract
The naturally occurring R68S substitution of phenylalanine hydroxylase (PheH) causes phenylketonuria (PKU). However, the molecular basis for how the R68S variant leads to PKU remains unclear. Kinetic characterization of R68S PheH establishes that the enzyme is fully active in the absence of allosteric binding of phenylalanine, in contrast to the WT enzyme. Analytical ultracentrifugation establishes that the isolated regulatory domain of R68S PheH is predominantly monomeric in the absence of phenylalanine and dimerizes in its presence, similar to the regulatory domain of the WT enzyme. Fluorescence and small-angle X-ray scattering analyses establish that the overall conformation of the resting form of R68S PheH is different from that of the WT enzyme. The data are consistent with the substitution disrupting the interface between the catalytic and regulatory domains of the enzyme, shifting the equilibrium between the resting and activated forms ∼200-fold, so that the resting form of R68S PheH is ∼70% in the activated conformation. However, R68S PheH loses activity 2 orders of magnitude more rapidly than the WT enzyme at 37 °C and is significantly more sensitive to proteolysis. We propose that, even though this substitution converts the enzyme to a constitutively active enzyme, it results in PKU because of the decrease in protein stability.
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Affiliation(s)
- Crystal A Khan
- From the Department of Biochemistry and Structural Biology, UT Health San Antonio, San Antonio, Texas 78229 and
| | - Steve P Meisburger
- the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Nozomi Ando
- the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Paul F Fitzpatrick
- From the Department of Biochemistry and Structural Biology, UT Health San Antonio, San Antonio, Texas 78229 and
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31
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Bai Y, Lang EJM, Nazmi AR, Parker EJ. Domain cross-talk within a bifunctional enzyme provides catalytic and allosteric functionality in the biosynthesis of aromatic amino acids. J Biol Chem 2019; 294:4828-4842. [PMID: 30670586 DOI: 10.1074/jbc.ra118.005220] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 01/15/2019] [Indexed: 12/15/2022] Open
Abstract
Because of their special organization, multifunctional enzymes play crucial roles in improving the performance of metabolic pathways. For example, the bacterium Prevotella nigrescens contains a distinctive bifunctional protein comprising a 3-deoxy-d-arabino heptulosonate-7-phosphate synthase (DAH7PS), catalyzing the first reaction of the biosynthetic pathway of aromatic amino acids, and a chorismate mutase (CM), functioning at a branch of this pathway leading to the synthesis of tyrosine and phenylalanine. In this study, we characterized this P. nigrescens enzyme and found that its two catalytic activities exhibit substantial hetero-interdependence and that the separation of its two distinct catalytic domains results in a dramatic loss of both DAH7PS and CM activities. The protein displayed a unique dimeric assembly, with dimerization solely via the CM domain. Small angle X-ray scattering (SAXS)-based structural analysis of this protein indicated a DAH7PS-CM hetero-interaction between the DAH7PS and CM domains, unlike the homo-association between DAH7PS domains normally observed for other DAH7PS proteins. This hetero-interaction provides a structural basis for the functional interdependence between the two domains observed here. Moreover, we observed that DAH7PS is allosterically inhibited by prephenate, the product of the CM-catalyzed reaction. This allostery was accompanied by a striking conformational change as observed by SAXS, implying that altering the hetero-domain interaction underpins the allosteric inhibition. We conclude that for this C-terminal CM-linked DAH7PS, catalytic function and allosteric regulation appear to be delivered by a common mechanism, revealing a distinct and efficient evolutionary strategy to utilize the functional advantages of a bifunctional enzyme.
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Affiliation(s)
- Yu Bai
- From the Maurice Wilkins Centre, Ferrier Research Institute, Victoria University of Wellington, Wellington 6012 and
| | - Eric J M Lang
- the Maurice Wilkins Centre, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch 8041, New Zealand
| | - Ali Reza Nazmi
- the Maurice Wilkins Centre, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch 8041, New Zealand
| | - Emily J Parker
- From the Maurice Wilkins Centre, Ferrier Research Institute, Victoria University of Wellington, Wellington 6012 and .,the Maurice Wilkins Centre, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch 8041, New Zealand
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32
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Gorman SD, D'Amico RN, Winston DS, Boehr DD. Engineering Allostery into Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1163:359-384. [PMID: 31707711 PMCID: PMC7508002 DOI: 10.1007/978-981-13-8719-7_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Our ability to engineer protein structure and function has grown dramatically over recent years. Perhaps the next level in protein design is to develop proteins whose function can be regulated in response to various stimuli, including ligand binding, pH changes, and light. Endeavors toward these goals have tested and expanded on our understanding of protein function and allosteric regulation. In this chapter, we provide examples from different methods for developing new allosterically regulated proteins. These methods range from whole insertion of regulatory domains into new host proteins, to covalent attachment of photoswitches to generate light-responsive proteins, and to targeted changes to specific amino acid residues, especially to residues identified to be important for relaying allosteric information across the protein framework. Many of the examples we discuss have already found practical use in medical and biotechnology applications.
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Affiliation(s)
- Scott D Gorman
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Rebecca N D'Amico
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Dennis S Winston
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - David D Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.
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33
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Szigetvari PD, Muruganandam G, Kallio JP, Hallin EI, Fossbakk A, Loris R, Kursula I, Møller LB, Knappskog PM, Kursula P, Haavik J. The quaternary structure of human tyrosine hydroxylase: effects of dystonia-associated missense variants on oligomeric state and enzyme activity. J Neurochem 2018; 148:291-306. [PMID: 30411798 PMCID: PMC6587854 DOI: 10.1111/jnc.14624] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 10/26/2018] [Accepted: 10/31/2018] [Indexed: 01/27/2023]
Abstract
Abstract Tyrosine hydroxylase (TH) is a multi‐domain, homo‐oligomeric enzyme that catalyses the rate‐limiting step of catecholamine neurotransmitter biosynthesis. Missense variants of human TH are associated with a recessive neurometabolic disease with low levels of brain dopamine and noradrenaline, resulting in a variable clinical picture, from progressive brain encephalopathy to adolescent onset DOPA‐responsive dystonia (DRD). We expressed isoform 1 of human TH (hTH1) and its dystonia‐associated missense variants in E. coli, analysed their quaternary structure and thermal stability using size‐exclusion chromatography, circular dichroism, multi‐angle light scattering, transmission electron microscopy, small‐angle X‐ray scattering and assayed hydroxylase activity. Wild‐type (WT) hTH1 was a mixture of enzymatically stable tetramers (85.6%) and octamers (14.4%), with little interconversion between these species. We also observed small amounts of higher order assemblies of long chains of enzyme by transmission electron microscopy. To investigate the role of molecular assemblies in the pathogenesis of DRD, we compared the structure of WT hTH1 with the DRD‐associated variants R410P and D467G that are found in vicinity of the predicted subunit interfaces. In contrast to WT hTH1, R410P and D467G were mixtures of tetrameric and dimeric species. Inspection of the available structures revealed that Arg‐410 and Asp‐467 are important for maintaining the stability and oligomeric structure of TH. Disruption of the normal quaternary enzyme structure by missense variants is a new molecular mechanism that may explain the loss of TH enzymatic activity in DRD. Unstable missense variants could be targets for pharmacological intervention in DRD, aimed to re‐establish the normal oligomeric state of TH. ![]()
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Affiliation(s)
- Peter D Szigetvari
- Department of Biomedicine, University of Bergen, Bergen, Norway.,K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Gopinath Muruganandam
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Juha P Kallio
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Erik I Hallin
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Agnete Fossbakk
- K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Remy Loris
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Inari Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Lisbeth B Møller
- Applied Human Molecular Genetics, Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Per M Knappskog
- K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway.,Department of Clinical Science, University of Bergen, Bergen, Norway.,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Bergen, Norway.,K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway.,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
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Ma D, Reichelt M, Yoshida K, Gershenzon J, Constabel CP. Two R2R3-MYB proteins are broad repressors of flavonoid and phenylpropanoid metabolism in poplar. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:949-965. [PMID: 30176084 DOI: 10.1111/tpj.14081] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 08/15/2018] [Accepted: 08/20/2018] [Indexed: 05/18/2023]
Abstract
The phenylpropanoid pathway leads to the production of many important plant secondary metabolites including lignin, chlorogenic acids, flavonoids, and phenolic glycosides. Early studies have demonstrated that flavonoid biosynthesis is transcriptionally regulated, often by a MYB, bHLH, and WDR transcription factor complex. In poplar, several R2R3 MYB transcription factors are known to be involved in flavonoid biosynthesis. Previous work determined that poplar MYB134 and MYB115 are major activators of the proanthocyanidin pathway, and also induce the expression of repressor-like MYB transcription factors. Here we characterize two new repressor MYBs, poplar MYB165 and MYB194, paralogs which comprise a subgroup of R2R3-MYBs distinct from previously reported poplar repressors. Both MYB165 and MYB194 repressed the activation of flavonoid promoters by MYB134 in transient activation assays, and both interacted with a co-expressed bHLH transcription factor, bHLH131, in yeast two-hybrid assays. Overexpression of MYB165 and MYB194 in hybrid poplar resulted in greatly reduced accumulation of several phenylpropanoids including anthocyanins, proanthocyanidins, phenolic glycosides, and hydroxycinnamic acid esters. Transcriptome analysis of MYB165- and MYB194-overexpressing poplars confirmed repression of many phenylpropanoid enzyme genes. In addition, other MYB genes as well as several shikimate pathway enzyme genes were downregulated by MYB165-overexpression. By contrast, leaf aromatic amino acid concentrations were greater in MYB165-overexpressing poplars. Our findings indicate that MYB165 is a major repressor of the flavonoid and phenylpropanoid pathway in poplar, and may also affect the shikimate pathway. The coordinated action of repressor and activator MYBs could be important for the fine tuning of proanthocyanidin biosynthesis during development or following stress.
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Affiliation(s)
- Dawei Ma
- Centre for Forest Biology & Department of Biology, University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada
| | - Michael Reichelt
- Department of Biochemistry, Max-Planck Institute for Chemical Ecology, Hans-Knöll Strasse 8, 07745, Jena, Germany
| | - Kazuko Yoshida
- Centre for Forest Biology & Department of Biology, University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada
| | - Jonathan Gershenzon
- Department of Biochemistry, Max-Planck Institute for Chemical Ecology, Hans-Knöll Strasse 8, 07745, Jena, Germany
| | - C Peter Constabel
- Centre for Forest Biology & Department of Biology, University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada
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Zhou Y, Wang C, Xiao Q, Guo L. Crystal structures of arginine sensor CASTOR1 in arginine-bound and ligand free states. Biochem Biophys Res Commun 2018; 508:387-391. [PMID: 30503338 DOI: 10.1016/j.bbrc.2018.11.147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 11/21/2018] [Indexed: 02/05/2023]
Abstract
The mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) is a master regulator of metabolism and cell growth. Among the numerous extracellular and intracellular signals, certain amino acids activate mTORC1 in a Rag-dependent manner. Arginine can stimulate mTORC1 activity by releasing the inhibitor CASTOR1 (Cellular Arginine Sensor of mTORC1) from GATOR2, a positive regulator of mTORC1 which interacts with GATOR1, the GAP for RagA/B. Three groups have resolved the structures of arginine-CASTOR1 complex, shedding a new light on molecular basis of the regulation of mTORC1 activity by arginine. However, lacking the apo structure of CASTOR1 prelimited the molecular understanding of mechanism underlying mTORC1 regulation. Here, we report crystal structures of arginine sensor CASTOR1 in arginine-bound and ligand free states at 2.05 Å and 2.8 Å, respectively. Structural comparison of CASTOR1 between two states reveals near identical conformations, except in two loop regions. It indicates CASTOR1 does not undergo large conformational change during arginine binding. Therefore, we conclude a detailed structural interpretation of arginine sensing by CASTOR1 in mTORC1 pathway.
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Affiliation(s)
- Yanxia Zhou
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Chen Wang
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Qingjie Xiao
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Li Guo
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
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36
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ACR11 modulates levels of reactive oxygen species and salicylic acid-associated defense response in Arabidopsis. Sci Rep 2018; 8:11851. [PMID: 30087396 PMCID: PMC6081435 DOI: 10.1038/s41598-018-30304-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 07/27/2018] [Indexed: 01/10/2023] Open
Abstract
The ACT domain (aspartate kinase, chorismate mutase and TyrA), an allosteric effector binding domain, is commonly found in amino acid metabolic enzymes. In addition to ACT domain-containing enzymes, plants have a novel family of ACT domain repeat (ACR) proteins, which do not contain any recognizable catalytic domain. Arabidopsis has 12 ACR proteins, whose functions are largely unknown. To study the functions of Arabidopsis ACR11, we have characterized two independent T-DNA insertion mutants, acr11-2 and acr11-3. RNA gel-blot analysis revealed that the expression of wild-type ACR11 transcripts was not detectable in the acr11 mutants. Interestingly, a lesion-mimic phenotype occurs in some rosette leaves of the acr11 mutants. In addition, high levels of reactive oxygen species (ROS), salicylic acid (SA), and callose accumulate in the mutant leaves when grown under normal conditions. The expression of several SA marker genes and the key SA biosynthetic gene ISOCHORISMATE SYNTHASE1 is up-regulated in the acr11 mutants. Furthermore, the acr11 mutants are more resistant to the infection of bacterial pathogen Pseudomonas syringae pathovar tomato DC3000. These results suggest that ACR11 may be directly or indirectly involved in the regulation of ROS and SA accumulation, which in turn modulates SA-associated defense responses and disease resistance in Arabidopsis.
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37
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Mechanistic insights into the allosteric regulation of Pseudomonas aeruginosa aspartate kinase. Biochem J 2018; 475:1107-1119. [PMID: 29382741 DOI: 10.1042/bcj20170829] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/18/2018] [Accepted: 01/24/2018] [Indexed: 02/05/2023]
Abstract
In plants and microorganisms, aspartate kinase (AK) catalyzes an initial commitment step of the aspartate family amino acid biosynthesis. Owing to various structural organizations, AKs from different species show tremendous diversity and complex allosteric controls. We report the crystal structure of AK from Pseudomonas aeruginosa (PaAK), a typical α2β2 hetero-tetrameric enzyme, in complex with inhibitory effectors. Distinctive features of PaAK are revealed by structural and biochemical analyses. Essentially, the open conformation of Lys-/Thr-bound PaAK structure clarifies the inhibitory mechanism of α2β2-type AK. Moreover, the various inhibitory effectors of PaAK have been identified and a general amino acid effector motif of AK family is described.
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38
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Abstract
Most proteins comprise two or more domains from a limited suite of protein families. These domains are often rearranged in various combinations through gene fusion events to evolve new protein functions, including the acquisition of protein allostery through the incorporation of regulatory domains. The enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAH7PS) is the first enzyme of aromatic amino acid biosynthesis and displays a diverse range of allosteric mechanisms. DAH7PSs adopt a common architecture with a shared (β/α)8 catalytic domain which can be attached to an ACT-like or a chorismate mutase regulatory domain that operates via distinct mechanisms. These respective domains confer allosteric regulation by controlling DAH7PS function in response to ligand Tyr or prephenate. Starting with contemporary DAH7PS proteins, two protein chimeras were created, with interchanged regulatory domains. Both engineered proteins were catalytically active and delivered new functional allostery with switched ligand specificity and allosteric mechanisms delivered by their nonhomologous regulatory domains. This interchangeability of protein domains represents an efficient method not only to engineer allostery in multidomain proteins but to create a new bifunctional enzyme.
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39
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Rozman Grinberg I, Lundin D, Hasan M, Crona M, Jonna VR, Loderer C, Sahlin M, Markova N, Borovok I, Berggren G, Hofer A, Logan DT, Sjöberg BM. Novel ATP-cone-driven allosteric regulation of ribonucleotide reductase via the radical-generating subunit. eLife 2018; 7:31529. [PMID: 29388911 PMCID: PMC5794259 DOI: 10.7554/elife.31529] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 12/23/2017] [Indexed: 12/27/2022] Open
Abstract
Ribonucleotide reductases (RNRs) are key enzymes in DNA metabolism, with allosteric mechanisms controlling substrate specificity and overall activity. In RNRs, the activity master-switch, the ATP-cone, has been found exclusively in the catalytic subunit. In two class I RNR subclasses whose catalytic subunit lacks the ATP-cone, we discovered ATP-cones in the radical-generating subunit. The ATP-cone in the Leeuwenhoekiella blandensis radical-generating subunit regulates activity via quaternary structure induced by binding of nucleotides. ATP induces enzymatically competent dimers, whereas dATP induces non-productive tetramers, resulting in different holoenzymes. The tetramer forms by interactions between ATP-cones, shown by a 2.45 Å crystal structure. We also present evidence for an MnIIIMnIV metal center. In summary, lack of an ATP-cone domain in the catalytic subunit was compensated by transfer of the domain to the radical-generating subunit. To our knowledge, this represents the first observation of transfer of an allosteric domain between components of the same enzyme complex. When a cell copies its DNA, it uses four different building blocks called deoxyribonucleotides (dNTPs). These consist of one of the four ‘bases’ (A, T, C and G), which pair up to link the two strands of DNA in the double helix, bound to a sugar and a phosphate group. If the cell contains too little or too much of one of these building blocks, an incorrect base may be inserted into the DNA. This results in a mutation, which in bacteria can cause death, and in animals may lead to cancer. The enzyme that fabricates and carefully controls the amount of each dNTP building block inside a cell is called ribonucleotide reductase. Once there are enough building blocks in a cell the enzyme is turned off. A part of the enzyme called the ATP-cone acts as an on/off switch to control this activity. The ribonucleotide reductase consists of a large component and a small component. Until now, studies of the ATP-cone have found it only in the large component of the enzyme. However, when looking through a public database of sequence data, Rozman Grinberg et al. noticed that ribonucleotide reductases in some bacteria have their ATP-cone joined to the small component. Does this ATP-cone also control the amounts of dNTP building blocks inside cells and, if so, how? Rozman Grinberg et al. studied one such ATP-cone in a ribonucleotide reductase from a bacterium (named Leeuwenhoekiella blandensis) found in the Mediterranean Sea. This revealed that when the amount of dNTP building blocks reaches a certain limit, the ATP-cone turns off the enzyme. Examining the three-dimensional structure of the enzyme using a technique called X-ray crystallography revealed that when turned off, the enzyme’s small components are glued together in pairs. This prevents them from working. Rozman Grinberg et al. also discovered that this enzyme contains a new type of metal center with two manganese ions suggesting that a new reaction mechanism may operate in this class of ribonucleotide reductase. These findings support a theory that biological on/off switches can evolve rapidly. In addition to its evolutionary and biomedical interest, understanding how the ATP-cone works might help to improve the enzymes used in industrial processes.
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Affiliation(s)
- Inna Rozman Grinberg
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Daniel Lundin
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Mahmudul Hasan
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | | | | | - Christoph Loderer
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Margareta Sahlin
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | | | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel Aviv-Yafo, Israel
| | - Gustav Berggren
- Department of Chemistry, Uppsala University, Uppsala, Sweden
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Derek T Logan
- Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Britt-Marie Sjöberg
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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40
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A dimeric catalytic core relates the short and long forms of ATP-phosphoribosyltransferase. Biochem J 2018; 475:247-260. [PMID: 29208762 DOI: 10.1042/bcj20170762] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 12/21/2022]
Abstract
Adenosine triphosphate (ATP) phosphoribosyltransferase (ATP-PRT) catalyses the first committed step of histidine biosynthesis in plants and microorganisms. Two forms of ATP-PRT have been reported, which differ in their molecular architecture and mechanism of allosteric regulation. The short-form ATP-PRT is a hetero-octamer, with four HisG chains that comprise only the catalytic domains and four separate chains of HisZ required for allosteric regulation by histidine. The long-form ATP-PRT is homo-hexameric, with each chain comprising two catalytic domains and a covalently linked regulatory domain that binds histidine as an allosteric inhibitor. Here, we describe a truncated long-form ATP-PRT from Campylobacter jejuni devoid of its regulatory domain (CjeATP-PRTcore). Results showed that CjeATP-PRTcore is dimeric, exhibits attenuated catalytic activity, and is insensitive to histidine, indicating that the covalently linked regulatory domain plays a role in both catalysis and regulation. Crystal structures were obtained for CjeATP-PRTcore in complex with both substrates, and for the first time, the complete product of the reaction. These structures reveal the key features of the active site and provide insights into how substrates move into position during catalysis.
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41
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Pisco JP, de Chiara C, Pacholarz KJ, Garza-Garcia A, Ogrodowicz RW, Walker PA, Barran PE, Smerdon SJ, de Carvalho LPS. Uncoupling conformational states from activity in an allosteric enzyme. Nat Commun 2017; 8:203. [PMID: 28781362 PMCID: PMC5545217 DOI: 10.1038/s41467-017-00224-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 06/13/2017] [Indexed: 02/07/2023] Open
Abstract
ATP-phosphoribosyltransferase (ATP-PRT) is a hexameric enzyme in conformational equilibrium between an open and seemingly active state and a closed and presumably inhibited form. The structure-function relationship of allosteric regulation in this system is still not fully understood. Here, we develop a screening strategy for modulators of ATP-PRT and identify 3-(2-thienyl)-l-alanine (TIH) as an allosteric activator of this enzyme. Kinetic analysis reveals co-occupancy of the allosteric sites by TIH and l-histidine. Crystallographic and native ion-mobility mass spectrometry data show that the TIH-bound activated form of the enzyme closely resembles the inhibited l-histidine-bound closed conformation, revealing the uncoupling between ATP-PRT open and closed conformations and its functional state. These findings suggest that dynamic processes are responsible for ATP-PRT allosteric regulation and that similar mechanisms might also be found in other enzymes bearing a ferredoxin-like allosteric domain. Active and inactive state ATP-phosphoribosyltransferases (ATP-PRTs) are believed to have different conformations. Here the authors show that in both states, ATP-PRT has a similar structural arrangement, suggesting that dynamic alterations are involved in ATP-PRT regulation by allosteric modulators.
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Affiliation(s)
- João P Pisco
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Cesira de Chiara
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Kamila J Pacholarz
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology & School of Chemistry, University of Manchester, Manchester, M1 7DN, UK
| | - Acely Garza-Garcia
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Roksana W Ogrodowicz
- Structural Biology Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Philip A Walker
- Structural Biology Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Perdita E Barran
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology & School of Chemistry, University of Manchester, Manchester, M1 7DN, UK
| | - Stephen J Smerdon
- Structural Biology of DNA-damage Signalling Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Luiz Pedro S de Carvalho
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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42
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Jaffe EK. New protein structures provide an updated understanding of phenylketonuria. Mol Genet Metab 2017; 121:289-296. [PMID: 28645531 PMCID: PMC5549558 DOI: 10.1016/j.ymgme.2017.06.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 06/08/2017] [Indexed: 11/16/2022]
Abstract
Phenylketonuria (PKU) and less severe hyperphenylalaninemia (HPA) constitute the most common inborn error of amino acid metabolism, and is most often caused by defects in phenylalanine hydroxylase (PAH) function resulting in accumulation of Phe to neurotoxic levels. Despite the success of dietary intervention in preventing permanent neurological damage, individuals living with PKU clamor for additional non-dietary therapies. The bulk of disease-associated mutations are PAH missense variants, which occur throughout the entire 452 amino acid human PAH protein. While some disease-associated mutations affect protein structure (e.g. truncations) and others encode catalytically dead variants, most have been viewed as defective in protein folding/stability. Here we refine this view to address how PKU-associated missense variants can perturb the equilibrium among alternate native PAH structures (resting-state PAH and activated PAH), thus shifting the tipping point of this equilibrium to a neurotoxic Phe concentration. This refined view of PKU introduces opportunities for the design or discovery of therapeutic pharmacological chaperones that can help restore the tipping point to healthy Phe levels and how such a therapeutic might work with or without the inhibitory pharmacological chaperone BH4. Dysregulation of an equilibrium of architecturally distinct native PAH structures departs from the concept of "misfolding", provides an updated understanding of PKU, and presents an enhanced foundation for understanding genotype/phenotype relationships.
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Affiliation(s)
- Eileen K Jaffe
- Fox Chase Cancer Center - Temple University Health System, 333 Cottman Ave, Philadelphia, PA 19111, USA.
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43
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Yao Y, Jones E, Inoki K. Lysosomal Regulation of mTORC1 by Amino Acids in Mammalian Cells. Biomolecules 2017; 7:biom7030051. [PMID: 28686218 PMCID: PMC5618232 DOI: 10.3390/biom7030051] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/03/2017] [Accepted: 07/04/2017] [Indexed: 12/15/2022] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth in eukaryotic cells. The active mTORC1 promotes cellular anabolic processes including protein, pyrimidine, and lipid biosynthesis, and inhibits catabolic processes such as autophagy. Consistent with its growth-promoting functions, hyper-activation of mTORC1 signaling is one of the important pathomechanisms underlying major human health problems including diabetes, neurodegenerative disorders, and cancer. The mTORC1 receives multiple upstream signals such as an abundance of amino acids and growth factors, thus it regulates a wide range of downstream events relevant to cell growth and proliferation control. The regulation of mTORC1 by amino acids is a fast-evolving field with its detailed mechanisms currently being revealed as the precise picture emerges. In this review, we summarize recent progress with respect to biochemical and biological findings in the regulation of mTORC1 signaling on the lysosomal membrane by amino acids.
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Affiliation(s)
- Yao Yao
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA.
| | - Edith Jones
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA.
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 East Catherine Street, Ann Arbor, MI 48109, USA.
| | - Ken Inoki
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA.
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 East Catherine Street, Ann Arbor, MI 48109, USA.
- Department of Internal Medicine, University of Michigan Medical School, 1500 East Medical enter Drive, Ann Arbor, MI 48109, USA.
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44
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Jiao W, Blackmore NJ, Nazmi AR, Parker EJ. Quaternary structure is an essential component that contributes to the sophisticated allosteric regulation mechanism in a key enzyme from Mycobacterium tuberculosis. PLoS One 2017; 12:e0180052. [PMID: 28665948 PMCID: PMC5493349 DOI: 10.1371/journal.pone.0180052] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 06/08/2017] [Indexed: 01/26/2023] Open
Abstract
The first enzyme of the shikimate pathway, 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (DAH7PS), adopts a range of distinct allosteric regulation mechanisms in different organisms, related to different quaternary assemblies. DAH7PS from Mycobacterium tuberculosis (MtuDAH7PS) is a homotetramer, with the allosteric sites in close proximity to the interfaces. Here we examine the importance of the quaternary structure on catalysis and regulation, by amino acid substitution targeting the tetramer interface of MtuDAH7PS. Using only single amino acid substitutions either in, or remote from the interface, two dimeric variants of MtuDAH7PS (MtuDAH7PSF227D and MtuDAH7PSG232P) were successfully generated. Both dimeric variants maintained activity due to the distance between the sites of amino acid substitution and the active sites, but attenuated catalytic efficiency was observed. Both dimeric variants showed significantly disrupted allosteric regulation with greatly impaired binding affinity for one of the allosteric ligands. Molecular dynamics simulations revealed changes in protein dynamics and average conformations in the dimeric variant caused by amino acid substitution remote to the tetramer interface (MtuDAH7PSG232P), which are consistent with the observed reduction in catalytic efficiency and loss of allosteric response.
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Affiliation(s)
- Wanting Jiao
- Maurice Wilkins Centre for Molecular Biodiscovery, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch, New Zealand
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Nicola J. Blackmore
- Maurice Wilkins Centre for Molecular Biodiscovery, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch, New Zealand
| | - Ali Reza Nazmi
- Maurice Wilkins Centre for Molecular Biodiscovery, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch, New Zealand
| | - Emily J. Parker
- Maurice Wilkins Centre for Molecular Biodiscovery, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch, New Zealand
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
- * E-mail:
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45
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Abstract
X-ray scattering is uniquely suited to the study of disordered systems and thus has the potential to provide insight into dynamic processes where diffraction methods fail. In particular, while X-ray crystallography has been a staple of structural biology for more than half a century and will continue to remain so, a major limitation of this technique has been the lack of dynamic information. Solution X-ray scattering has become an invaluable tool in structural and mechanistic studies of biological macromolecules where large conformational changes are involved. Such systems include allosteric enzymes that play key roles in directing metabolic fluxes of biochemical pathways, as well as large, assembly-line type enzymes that synthesize secondary metabolites with pharmaceutical applications. Furthermore, crystallography has the potential to provide information on protein dynamics via the diffuse scattering patterns that are overlaid with Bragg diffraction. Historically, these patterns have been very difficult to interpret, but recent advances in X-ray detection have led to a renewed interest in diffuse scattering analysis as a way to probe correlated motions. Here, we will review X-ray scattering theory and highlight recent advances in scattering-based investigations of protein solutions and crystals, with a particular focus on complex enzymes.
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Affiliation(s)
- Steve P Meisburger
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - William C Thomas
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Maxwell B Watkins
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Nozomi Ando
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
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46
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Anderson MS, Muff TJ, Georgianna DR, Mayfield SP. Towards a synthetic nuclear transcription system in green algae: Characterization of Chlamydomonas reinhardtii nuclear transcription factors and identification of targeted promoters. ALGAL RES 2017. [DOI: 10.1016/j.algal.2016.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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47
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Gai Z, Wang Q, Yang C, Wang L, Deng W, Wu G. Structural mechanism for the arginine sensing and regulation of CASTOR1 in the mTORC1 signaling pathway. Cell Discov 2016; 2:16051. [PMID: 28066558 PMCID: PMC5187391 DOI: 10.1038/celldisc.2016.51] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/12/2016] [Indexed: 12/12/2022] Open
Abstract
The mTOR complex I (mTORC1) signaling pathway controls many metabolic processes and is regulated by amino acid signals, especially arginine. CASTOR1 has been identified as the cytosolic arginine sensor for the mTORC1 pathway, but the molecular mechanism of how it senses arginine is elusive. Here, by determining the crystal structure of human CASTOR1 in complex with arginine, we found that an exquisitely tailored pocket, carved between the NTD and the CTD domains of CASTOR1, is employed to recognize arginine. Mutation of critical residues in this pocket abolished or diminished arginine binding. By comparison with structurally similar aspartate kinases, a surface patch of CASTOR1-NTD on the opposite side of the arginine-binding site was identified to mediate direct physical interaction with its downstream effector GATOR2, via GATOR2 subunit Mios. Mutation of this surface patch disrupted CASTOR1’s recognition and inhibition of GATOR2, revealed by in vitro pull-down assay. Normal mode (NM) analysis revealed an ‘open’-to-‘closed’ conformational change for CASTOR1, which is correlated to the switching between the exposing and concealing of its GATOR2-binding residues, and is most likely related to arginine binding. Interestingly, the GATOR2-binding sites on the two protomers of CASTOR1 dimer face the same direction, which prompted us to propose a model for how dimerization of CASTOR1 relieves the inhibition of GATOR1 by GATOR2. Our study thus provides a thorough analysis on how CASTOR1 recognizes arginine, and describes a possible mechanism of how arginine binding induces the inter-domain movement of CASTOR1 to affect its association with GATOR2.
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Affiliation(s)
- Zhongchao Gai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University , Shanghai, China
| | - Qian Wang
- National Center for Protein Science Shanghai , Shanghai, China
| | - Can Yang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University , Shanghai, China
| | - Lei Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University , Shanghai, China
| | - Wei Deng
- National Center for Protein Science Shanghai , Shanghai, China
| | - Geng Wu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University , Shanghai, China
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48
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Tidemand KD, Christensen HEM, Hoeck N, Harris P, Boesen J, Peters GH. Stabilization of tryptophan hydroxylase 2 by l-phenylalanine-induced dimerization. FEBS Open Bio 2016; 6:987-999. [PMID: 27761358 PMCID: PMC5055035 DOI: 10.1002/2211-5463.12100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/20/2016] [Accepted: 06/29/2016] [Indexed: 12/12/2022] Open
Abstract
Tryptophan hydroxylase 2 (TPH2) catalyses the initial and rate‐limiting step in the biosynthesis of serotonin, which is associated with a variety of disorders such as depression, obsessive compulsive disorder, and schizophrenia. Full‐length TPH2 is poorly characterized due to low purification quantities caused by its inherent instability. Three truncated variants of human TPH2 (rchTPH2; regulatory and catalytic domain, NΔ47‐rchTPH2; truncation of 47 residues in the N terminus of rchTPH2, and chTPH2; catalytic domain) were expressed, purified, and examined for changes in transition temperature, inactivation rate, and oligomeric state. chTPH2 displayed 14‐ and 11‐fold higher half‐lives compared to rchTPH2 and NΔ47‐rchTPH2, respectively. Differential scanning calorimetry experiments demonstrated that this is caused by premature unfolding of the less stable regulatory domain. By differential scanning fluorimetry, the unfolding transitions of rchTPH2 and NΔ47‐rchTPH2 are found to shift from polyphasic to apparent two‐state by the addition of l‐Trp or l‐Phe. Analytical gel filtration revealed that rchTPH2 and NΔ47‐rchTPH2 reside in a monomer–dimer equilibrium which is significantly shifted toward dimer in the presence of l‐Phe. The dimerizing effect induced by l‐Phe is accompanied by a stabilizing effect, which resulted in a threefold increase in half‐lives of rchTPH2 and NΔ47‐rchTPH2. Addition of l‐Phe to the purification buffer significantly increases the purification yields, which will facilitate characterization of hTPH2.
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Affiliation(s)
- Kasper D Tidemand
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | | | - Niclas Hoeck
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Pernille Harris
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Jane Boesen
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Günther H Peters
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
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49
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Nazmi AR, Lang EJM, Bai Y, Allison TM, Othman MH, Panjikar S, Arcus VL, Parker EJ. Interdomain Conformational Changes Provide Allosteric Regulation en Route to Chorismate. J Biol Chem 2016; 291:21836-21847. [PMID: 27502275 DOI: 10.1074/jbc.m116.741637] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/30/2016] [Indexed: 11/06/2022] Open
Abstract
Multifunctional proteins play a variety of roles in metabolism. Here, we examine the catalytic function of the combined 3-deoxy-d-arabino heptulosonate-7-phosphate synthase (DAH7PS) and chorismate mutase (CM) from Geobacillus sp. DAH7PS operates at the start of the biosynthetic pathway for aromatic metabolites, whereas CM operates in a dedicated branch of the pathway for the biosynthesis of amino acids tyrosine and phenylalanine. In line with sequence predictions, the two catalytic functions are located in distinct domains, and these two activities can be separated and retain functionality. For the full-length protein, prephenate, the product of the CM reaction, acts as an allosteric inhibitor for the DAH7PS. The crystal structure of the full-length protein with prephenate bound and the accompanying small angle x-ray scattering data reveal the molecular mechanism of the allostery. Prephenate binding results in the tighter association between the dimeric CM domains and the tetrameric DAH7PS, occluding the active site and therefore disrupting DAH7PS function. Acquisition of a physical gating mechanism to control catalytic function through gene fusion appears to be a general mechanism for providing allostery for this enzyme.
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Affiliation(s)
- Ali Reza Nazmi
- From the Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand
| | - Eric J M Lang
- From the Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand
| | - Yu Bai
- From the Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand
| | - Timothy M Allison
- the Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 5QY, United Kingdom
| | - Mohamad H Othman
- From the Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand
| | - Santosh Panjikar
- the Australian Synchrotron, Clayton, Melbourne, Victoria 3168, Australia.,the Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
| | - Vickery L Arcus
- the School of Science, University of Waikato, Hamilton 3240, New Zealand, and
| | - Emily J Parker
- the Maurice Wilkins Centre, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand
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50
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Livingstone EK, Mittelstädt G, Given FM, Parker EJ. Independent catalysis of the short form HisG from Lactococcus lactis. FEBS Lett 2016; 590:2603-10. [PMID: 27393206 DOI: 10.1002/1873-3468.12277] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/07/2016] [Accepted: 06/25/2016] [Indexed: 12/26/2022]
Abstract
ATP-phosphoribosyltransferase (ATP-PRT) catalyses the first step of histidine biosynthesis. Two different forms of ATP-PRT have been described; the homo-hexameric long form, and the hetero-octameric short form. Lactococcus lactis possesses the short form ATP-PRT comprising four subunits of HisGS , the catalytic subunit, and four subunits of HisZ, a histidyl-tRNA synthetase paralogue. Previous studies have suggested that HisGS requires HisZ for catalysis. Here, we reveal that the dimeric HisGS does display ATP-PRT activity in the absence of HisZ. This result reflects the evolutionary relationship between the long and short form ATP-PRT, which acquired allosteric inhibition and enhanced catalysis via two divergent strategies.
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Affiliation(s)
- Emma K Livingstone
- Department of Chemistry and Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
| | - Gerd Mittelstädt
- Department of Chemistry and Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
| | - Fiona M Given
- Department of Chemistry and Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
| | - Emily J Parker
- Department of Chemistry and Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
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