1
|
Wang W, Xiang Y, Yin G, Hu S, Cheng J, Chen J, Du G, Kang Z, Wang Y. Construction of 5-Aminolevulinic Acid Microbial Cell Factories through Identification of Novel Synthases and Metabolic Pathway Screens and Transporters. J Agric Food Chem 2024; 72:8006-8017. [PMID: 38554273 DOI: 10.1021/acs.jafc.4c00903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/01/2024]
Abstract
5-Aminolevulinic acid (5-ALA) plays a pivotal role in the biosynthesis of heme and chlorophyll and has garnered great attention for its agricultural applications. This study explores the multifaceted construction of 5-ALA microbial cell factories. Evolutionary analysis-guided screening identified a novel 5-ALA synthase from Sphingobium amiense as the best synthase. An sRNA library facilitated global gene screening that demonstrated that trpC and ilvA repression enhanced 5-ALA production by 74.3% and 102%, respectively. Subsequently, efflux of 5-ALA by the transporter Gdx increased 5-ALA biosynthesis by 25.7%. To mitigate oxidative toxicity, DNA-binding proteins from starved cells were employed, enhancing cell density and 5-ALA titer by 21.1 and 4.1%, respectively. Combining these strategies resulted in an Escherichia coli strain that produced 5-ALA to 1.51 g·L-1 in shake flask experiments and 6.19 g·L-1 through fed-batch fermentation. This study broadens the repertoire of available 5-ALA synthases and transporters and provides a new platform for optimizing 5-ALA bioproduction.
Collapse
Affiliation(s)
- Wenqiu Wang
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiaxing Institute of Future Food, Jiaxing 314050, China
| | - Yulong Xiang
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Guobin Yin
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Shan Hu
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Jiaxing Institute of Future Food, Jiaxing 314050, China
| | - Jian Cheng
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jian Chen
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Guocheng Du
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhen Kang
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Yang Wang
- The Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| |
Collapse
|
2
|
Kawaguchi J, Mori H, Iwai N, Wachi M. A secondary metabolic enzyme functioned as an evolutionary seed of a primary metabolic enzyme. Mol Biol Evol 2022; 39:6651898. [PMID: 35904937 PMCID: PMC9356726 DOI: 10.1093/molbev/msac164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The antibiotic alaremycin has a structure that resembles that of 5-aminolevulinic acid (ALA), a universal precursor of porphyrins, and inhibits porphyrin biosynthesis. Genome sequencing of the alaremycin-producing bacterial strain and enzymatic analysis revealed that the first step of alaremcyin biosynthesis is catalysed by the enzyme, AlmA, which exhibits a high degree of similarity to 5-aminolevulinate synthase (ALAS) expressed by animals, protozoa, fungi and α-proteobacteria. Site-directed mutagenesis of AlmA revealed that the substitution of two amino acids residues around the substrate binding pocket transformed its substrate specificity from that of alaremycin precursor synthesis to ALA synthesis. To estimate the evolutionary trajectory of AlmA and ALAS, we performed an ancestral sequence reconstitution analysis based on a phylogenetic tree of AlmA and ALAS. The reconstructed common ancestral enzyme of AlmA and ALAS exhibited alaremycin precursor synthetic activity, rather than ALA synthetic activity. These results suggest that ALAS evolved from an AlmA-like enzyme. We propose a new evolutionary hypothesis in which a non-essential secondary metabolic enzyme acts as an 'evolutionary seed' to generate an essential primary metabolic enzyme.
Collapse
Affiliation(s)
- Jun Kawaguchi
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Hikaru Mori
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Noritaka Iwai
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Masaaki Wachi
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| |
Collapse
|
3
|
Rondelli CM, Perfetto M, Danoff A, Bergonia H, Gillis S, O'Neill L, Jackson L, Nicolas G, Puy H, West R, Phillips JD, Yien YY. The ubiquitous mitochondrial protein unfoldase CLPX regulates erythroid heme synthesis by control of iron utilization and heme synthesis enzyme activation and turnover. J Biol Chem 2021; 297:100972. [PMID: 34280433 PMCID: PMC8361296 DOI: 10.1016/j.jbc.2021.100972] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 07/13/2021] [Accepted: 07/15/2021] [Indexed: 11/19/2022] Open
Abstract
Heme plays a critical role in catalyzing life-essential redox reactions in all cells, and its synthesis must be tightly balanced with cellular requirements. Heme synthesis in eukaryotes is tightly regulated by the mitochondrial AAA+ unfoldase CLPX (caseinolytic mitochondrial matrix peptidase chaperone subunit X), which promotes heme synthesis by activation of δ-aminolevulinate synthase (ALAS/Hem1) in yeast and regulates turnover of ALAS1 in human cells. However, the specific mechanisms by which CLPX regulates heme synthesis are unclear. In this study, we interrogated the mechanisms by which CLPX regulates heme synthesis in erythroid cells. Quantitation of enzyme activity and protein degradation showed that ALAS2 stability and activity were both increased in the absence of CLPX, suggesting that CLPX primarily regulates ALAS2 by control of its turnover, rather than its activation. However, we also showed that CLPX is required for PPOX (protoporphyrinogen IX oxidase) activity and maintenance of FECH (ferrochelatase) levels, which are the terminal enzymes in heme synthesis, likely accounting for the heme deficiency and porphyrin accumulation observed in Clpx−/− cells. Lastly, CLPX is required for iron utilization for hemoglobin synthesis during erythroid differentiation. Collectively, our data show that the role of CLPX in yeast ALAS/Hem1 activation is not conserved in vertebrates as vertebrates rely on CLPX to regulate ALAS turnover as well as PPOX and FECH activity. Our studies reveal that CLPX mutations may cause anemia and porphyria via dysregulation of ALAS, FECH, and PPOX activities, as well as of iron metabolism.
Collapse
Affiliation(s)
- Catherine M Rondelli
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| | - Mark Perfetto
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Pittsburgh Heart, Lung and Blood Vascular Medicine Institute and Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Aidan Danoff
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| | - Hector Bergonia
- Division of Hematology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Samantha Gillis
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| | - Leah O'Neill
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| | - Laurie Jackson
- Division of Hematology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Gael Nicolas
- Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France
| | - Herve Puy
- Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Centre Français des Porphyries, Hôpital Louis Mourier, APHP, Colombes, France
| | - Richard West
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - John D Phillips
- Division of Hematology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Yvette Y Yien
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Pittsburgh Heart, Lung and Blood Vascular Medicine Institute and Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
| |
Collapse
|
4
|
Stojanovski BM, Hunter GA, Na I, Uversky VN, Jiang RHY, Ferreira GC. 5-Aminolevulinate synthase catalysis: The catcher in heme biosynthesis. Mol Genet Metab 2019; 128:178-189. [PMID: 31345668 PMCID: PMC6908770 DOI: 10.1016/j.ymgme.2019.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/27/2019] [Accepted: 06/07/2019] [Indexed: 01/26/2023]
Abstract
5-Aminolevulinate (ALA) synthase (ALAS), a homodimeric pyridoxal-5'-phosphate (PLP)-dependent enzyme, catalyzes the first step of heme biosynthesis in metazoa, fungi and α-proteobacteria. In this review, we focus on the advances made in unraveling the mechanism of the ALAS-catalyzed reaction during the past decade. The interplay between the PLP cofactor and the protein moiety determines and modulates the multi-intermediate reaction cycle of ALAS, which involves the decarboxylative condensation of two substrates, glycine and succinyl-CoA. Substrate binding and catalysis are rapid, and product (ALA) release dominates the overall ALAS kinetic mechanism. Interconversion between a catalytically incompetent, open conformation and a catalytically competent, closed conformation is linked to ALAS catalysis. Reversion to the open conformation, coincident with ALA dissociation, defines the slowest step of the reaction cycle. These findings were further substantiated by introducing seven mutations in the16-amino acid loop that gates the active site, yielding an ALAS variant with a greatly increased rate of catalytic turnover and heightened specificity constants for both substrates. Recently, molecular dynamics (MD) simulation analysis of various dimeric ALAS forms revealed that the seven active site loop mutations caused the proteins to adopt different conformations. In particular, the emergence of a β-strand in the mutated loop, which interacted with two preexisting β-strands to form an anti-parallel three-stranded β-sheet, conferred the murine heptavariant with a more stable open conformation and prompted faster product release than wild-type mALAS2. Moreover, the dynamics of the mALAS2 active site loop anti-correlated with that of the 35 amino acid C-terminal sequence. This led us to propose that this C-terminal extension, which is absent in prokaryotic ALASs, finely tunes mammalian ALAS activity. Based on the above results, we extend our previous proposal to include that discovery of a ligand inducing the mammalian C-terminal extension to fold offers a good prospect for the development of a new drug for X-linked protoporphyria and/or other porphyrias associated with enhanced ALAS activity and/or porphyrin accumulation.
Collapse
Affiliation(s)
- Bosko M Stojanovski
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Gregory A Hunter
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Insung Na
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
| | - Rays H Y Jiang
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Gloria C Ferreira
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA; Department of Chemistry, College of Arts and Sciences, University of South Florida, Tampa, FL 33612, USA.
| |
Collapse
|
5
|
Liu J, Kaganjo J, Zhang W, Zeilstra-Ryalls J. Investigating the bifunctionality of cyclizing and "classical" 5-aminolevulinate synthases. Protein Sci 2017; 27:402-410. [PMID: 29027286 DOI: 10.1002/pro.3324] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/10/2017] [Accepted: 10/10/2017] [Indexed: 11/07/2022]
Abstract
The precursor to all tetrapyrroles is 5-aminolevulinic acid, which is made either via the condensation of glycine and succinyl-CoA catalyzed by an ALA synthase (the C4 or Shemin pathway) or by a pathway that uses glutamyl-tRNA as a precursor and involves other enzymes (the C5 pathway). Certain ALA synthases also catalyze the cyclization of ALA-CoA to form 2-amino-3-hydroxycyclopent-2-en-1-one. Organisms with synthases that possess this second activity nevertheless rely upon the C5 pathway to supply ALA for tetrapyrrole biosynthesis. The C5 N units are components of a variety of secondary metabolites. Here, we show that an ALA synthase used exclusively for tetrapyrrole biosynthesis is also capable of catalyzing the cyclization reaction, albeit at much lower efficiency than the dedicated cyclases. Two absolutely conserved serines present in all known ALA-CoA cyclases are threonines in all known ALA synthases, suggesting they could be important in distinguishing the functions of these enzymes. We found that purified mutant proteins having single and double substitutions of the conserved residues are not improved in their respective alternate activities; rather, they are worse. Protein structural modeling and amino acid sequence alignments were explored within the context of what is known about the reaction mechanisms of these two different types of enzymes to consider what other features are important for the two activities.
Collapse
Affiliation(s)
- Joyce Liu
- Department of Bioengineering, University of California, Berkeley, California
| | - James Kaganjo
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio
| | - Wenjun Zhang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California
| | - Jill Zeilstra-Ryalls
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio
| |
Collapse
|
6
|
Na I, DeForte S, Stojanovski BM, Ferreira GC, Uversky VN. Molecular dynamics analysis of the structural and dynamic properties of the functionally enhanced hepta-variant of mouse 5-aminolevulinate synthase. J Biomol Struct Dyn 2017; 36:152-165. [PMID: 27928941 DOI: 10.1080/07391102.2016.1269688] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Heme biosynthesis, a complex, multistage, and tightly controlled process, starts with 5-aminolevulinate (ALA) production, which, in metazoa and certain bacteria, is a reaction catalyzed by 5-aminolevulinate synthase (ALAS), a pyridoxal 5'-phosphate (PLP)-dependent enzyme. Functional aberrations in ALAS are associated with several human diseases. ALAS can adopt open and closed conformations, with segmental rearrangements of a C-terminal, 16-amino acid loop and an α-helix regulating accessibility to the ALAS active site. Of the murine erythroid ALAS (mALAS2) forms previously engineered to assess the role of the flexible C-terminal loop versus mALAS2 function one stood out due to its impressive gain in catalytic power. To elucidate how the simultaneously introduced seven mutations of this activity-enhanced variant affected structural and dynamic properties of mALAS2, we conducted extensive molecular dynamics simulation analysis of the dimeric forms of wild-type mALAS2, hepta-variant and Rhodobacter capsulatus ALAS (aka R. capsulatus HemA). This analysis revealed that the seven simultaneous mutations in the C-terminal loop, which extends over the active site of the enzyme, caused the bacterial and murine proteins to adopt different conformations. Specifically, a new β-strand in the mutated 'loop' led to interaction with two preexisting β-strands and formation of an anti-parallel three-stranded β-sheet, which likely endowed the murine hepta-variant a more 'stable' open conformation than that of wild-type mALAS2, consistent with a kinetic mechanism involving a faster closed-to-open conformation transition and product release for the mutated than wild-type enzyme. Further, the dynamic behavior of the mALAS2 protomers was strikingly different in the two dimeric forms.
Collapse
Affiliation(s)
- Insung Na
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Shelly DeForte
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Bosko M Stojanovski
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Gloria C Ferreira
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA.,b Department of Chemistry , College of Arts and Sciences, University of South Florida , Tampa , FL 33612 , USA
| | - Vladimir N Uversky
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA.,c USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine , University of South Florida , Tampa , Florida 33612 , USA.,d Laboratory of Structural Dynamics, Stability and Folding of Proteins , Institute of Cytology, Russian Academy of Sciences , St. Petersburg , Russia
| |
Collapse
|
7
|
Kubota Y, Nomura K, Katoh Y, Yamashita R, Kaneko K, Furuyama K. Novel Mechanisms for Heme-dependent Degradation of ALAS1 Protein as a Component of Negative Feedback Regulation of Heme Biosynthesis. J Biol Chem 2016; 291:20516-29. [PMID: 27496948 DOI: 10.1074/jbc.m116.719161] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Indexed: 12/30/2022] Open
Abstract
In eukaryotic cells, heme production is tightly controlled by heme itself through negative feedback-mediated regulation of nonspecific 5-aminolevulinate synthase (ALAS1), which is a rate-limiting enzyme for heme biosynthesis. However, the mechanism driving the heme-dependent degradation of the ALAS1 protein in mitochondria is largely unknown. In the current study, we provide evidence that the mitochondrial ATP-dependent protease ClpXP, which is a heteromultimer of CLPX and CLPP, is involved in the heme-dependent degradation of ALAS1 in mitochondria. We found that ALAS1 forms a complex with ClpXP in a heme-dependent manner and that siRNA-mediated suppression of either CLPX or CLPP expression induced ALAS1 accumulation in the HepG2 human hepatic cell line. We also found that a specific heme-binding motif on ALAS1, located at the N-terminal end of the mature protein, is required for the heme-dependent formation of this protein complex. Moreover, hemin-mediated oxidative modification of ALAS1 resulted in the recruitment of LONP1, another ATP-dependent protease in the mitochondrial matrix, into the ALAS1 protein complex. Notably, the heme-binding site in the N-terminal region of the mature ALAS1 protein is also necessary for the heme-dependent oxidation of ALAS1. These results suggest that ALAS1 undergoes a conformational change following the association of heme to the heme-binding motif on this protein. This change in the structure of ALAS1 may enhance the formation of complexes between ALAS1 and ATP-dependent proteases in the mitochondria, thereby accelerating the degradation of ALAS1 protein to maintain appropriate intracellular heme levels.
Collapse
Affiliation(s)
- Yoshiko Kubota
- From the Department of Molecular Biochemistry, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 and
| | - Kazumi Nomura
- From the Department of Molecular Biochemistry, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 and
| | - Yasutake Katoh
- the Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Rina Yamashita
- From the Department of Molecular Biochemistry, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 and
| | - Kiriko Kaneko
- From the Department of Molecular Biochemistry, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 and
| | - Kazumichi Furuyama
- From the Department of Molecular Biochemistry, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 and
| |
Collapse
|
8
|
Stojanovski BM, Ferreira GC. Asn-150 of Murine Erythroid 5-Aminolevulinate Synthase Modulates the Catalytic Balance between the Rates of the Reversible Reaction. J Biol Chem 2015; 290:30750-61. [PMID: 26511319 DOI: 10.1074/jbc.m115.655399] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 11/06/2022] Open
Abstract
5-Aminolevulinate synthase (ALAS) catalyzes the first step in mammalian heme biosynthesis, the pyridoxal 5'-phosphate (PLP)-dependent and reversible reaction between glycine and succinyl-CoA to generate CoA, CO2, and 5-aminolevulinate (ALA). Apart from coordinating the positioning of succinyl-CoA, Rhodobacter capsulatus ALAS Asn-85 has a proposed role in regulating the opening of an active site channel. Here, we constructed a library of murine erythroid ALAS variants with substitutions at the position occupied by the analogous bacterial asparagine, screened for ALAS function, and characterized the catalytic properties of the N150H and N150F variants. Quinonoid intermediate formation occurred with a significantly reduced rate for either the N150H- or N150F-catalyzed condensation of glycine with succinyl-CoA during a single turnover. The introduced mutations caused modifications in the ALAS active site such that the resulting variants tipped the balance between the forward- and reverse-catalyzed reactions. Although wild-type ALAS catalyzes the conversion of ALA into the quinonoid intermediate at a rate 6.3-fold slower than the formation of the same quinonoid intermediate from glycine and succinyl-CoA, the N150F variant catalyzes the forward reaction at a mere 1.2-fold faster rate than that of the reverse reaction, and the N150H variant reverses the rate values with a 1.7-fold faster rate for the reverse reaction than that for the forward reaction. We conclude that the evolutionary selection of Asn-150 was significant for optimizing the forward enzymatic reaction at the expense of the reverse, thus ensuring that ALA is predominantly available for heme biosynthesis.
Collapse
Affiliation(s)
| | - Gloria C Ferreira
- From the Department of Molecular Medicine, Morsani College of Medicine, and the Department of Chemistry, University of South Florida, Tampa, Florida 33612
| |
Collapse
|
9
|
Petříčková K, Chroňáková A, Zelenka T, Chrudimský T, Pospíšil S, Petříček M, Krištůfek V. Evolution of cyclizing 5-aminolevulinate synthases in the biosynthesis of actinomycete secondary metabolites: outcomes for genetic screening techniques. Front Microbiol 2015; 6:814. [PMID: 26300877 PMCID: PMC4525017 DOI: 10.3389/fmicb.2015.00814] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/23/2015] [Indexed: 11/13/2022] Open
Abstract
A combined approach, comprising PCR screening and genome mining, was used to unravel the diversity and phylogeny of genes encoding 5-aminolevulinic acid synthases (ALASs, hemA gene products) in streptomycetes-related strains. In actinomycetes, these genes were believed to be directly connected with the production of secondary metabolites carrying the C5N unit, 2-amino-3-hydroxycyclopent-2-enone, with biological activities making them attractive for future use in medicine and agriculture. Unlike "classical" primary metabolism ALAS, the C5N unit-forming cyclizing ALAS (cALAS) catalyses intramolecular cyclization of nascent 5-aminolevulinate. Specific amino acid sequence changes can be traced by comparison of "classical" ALASs against cALASs. PCR screening revealed 226 hemA gene-carrying strains from 1,500 tested, with 87% putatively encoding cALAS. Phylogenetic analysis of the hemA homologs revealed strain clustering according to putative type of metabolic product, which could be used to select producers of specific C5N compound classes. Supporting information was acquired through analysis of actinomycete genomic sequence data available in GenBank and further genetic or metabolic characterization of selected strains. Comparison of 16S rRNA taxonomic identification and BOX-PCR profiles provided evidence for numerous horizontal gene transfers of biosynthetic genes or gene clusters within actinomycete populations and even from non-actinomycete organisms. Our results underline the importance of environmental and evolutionary data in the design of efficient techniques for identification of novel producers.
Collapse
Affiliation(s)
- Kateřina Petříčková
- Institute of Microbiology, Czech Academy of Sciences, v. v. i. Prague, Czech Republic
| | - Alica Chroňáková
- Institute of Soil Biology, Biology Centre, Czech Academy of Sciences, v. v. i. České Budějovice, Czech Republic
| | - Tomáš Zelenka
- Institute of Microbiology, Czech Academy of Sciences, v. v. i. Prague, Czech Republic
| | - Tomáš Chrudimský
- Institute of Soil Biology, Biology Centre, Czech Academy of Sciences, v. v. i. České Budějovice, Czech Republic
| | - Stanislav Pospíšil
- Institute of Microbiology, Czech Academy of Sciences, v. v. i. Prague, Czech Republic
| | - Miroslav Petříček
- Institute of Microbiology, Czech Academy of Sciences, v. v. i. Prague, Czech Republic
| | - Václav Krištůfek
- Institute of Soil Biology, Biology Centre, Czech Academy of Sciences, v. v. i. České Budějovice, Czech Republic
| |
Collapse
|
10
|
Hunter GA, Ferreira GC. 5-aminolevulinate synthase: catalysis of the first step of heme biosynthesis. Cell Mol Biol (Noisy-le-grand) 2009; 55:102-110. [PMID: 19268008 PMCID: PMC2864774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Accepted: 01/17/2009] [Indexed: 05/27/2023]
Abstract
5-Aminolevulinate synthase is a homodimeric pyridoxal 5'-phosphate-dependent enzyme that catalyzes the first step of the heme biosynthetic pathway in animals, fungi, and the alpha-subclass of the photosynthetic purple bacteria. The reaction cycle involves condensation of glycine with succinyl-coenzyme A to yield 5-aminolevulinate, carbon dioxide, and CoA. Mutations in the human erythroid-specific aminolevulinate synthase gene are associated with the erythropoietic disorder X-linked sideroblastic anemia. Recent kinetic and crystallographic data have facilitated an unprecedented understanding of how this important enzyme produces 5-aminolevulinate, and suggest possible directions for future research that may lead to treatments not only for X-linked sideroblastic anemia, but also other diseases.
Collapse
Affiliation(s)
- G. A. Hunter
- Department of Molecular Medicine, College of Medicine, University of South Florida, Tampa, Florida 33612, USA
| | - G. C. Ferreira
- Department of Molecular Medicine, College of Medicine, University of South Florida, Tampa, Florida 33612, USA
- H. Lee Moffitt Cancer Center and Research Institute, University of South Florida, Tampa, Florida 33612, USA
| |
Collapse
|