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Kammel M, Erdmann C, Sawers RG. The formate-hydrogen axis and its impact on the physiology of enterobacterial fermentation. Adv Microb Physiol 2024; 84:51-82. [PMID: 38821634 DOI: 10.1016/bs.ampbs.2024.02.002] [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: 06/02/2024]
Abstract
Formic acid (HCOOH) and dihydrogen (H2) are characteristic products of enterobacterial mixed-acid fermentation, with H2 generation increasing in conjunction with a decrease in extracellular pH. Formate and acetyl-CoA are generated by radical-based and coenzyme A-dependent cleavage of pyruvate catalysed by pyruvate formate-lyase (PflB). Formate is also the source of H2, which is generated along with carbon dioxide through the action of the membrane-associated, cytoplasmically-oriented formate hydrogenlyase (FHL-1) complex. Synthesis of the FHL-1 complex is completely dependent on the cytoplasmic accumulation of formate. Consequently, formate determines its own disproportionation into H2 and CO2 by the FHL-1 complex. Cytoplasmic formate levels are controlled by FocA, a pentameric channel that translocates formic acid/formate bidirectionally between the cytoplasm and periplasm. Each protomer of FocA has a narrow hydrophobic pore through which neutral formic acid can pass. Two conserved amino acid residues, a histidine and a threonine, at the center of the pore control directionality of translocation. The histidine residue is essential for pH-dependent influx of formic acid. Studies with the formate analogue hypophosphite and amino acid variants of FocA suggest that the mechanisms of formic acid efflux and influx differ. Indeed, current data suggest, depending on extracellular formate levels, two separate uptake mechanisms exist, both likely contributing to maintain pH homeostasis. Bidirectional formate/formic acid translocation is dependent on PflB and influx requires an active FHL-1 complex. This review describes the coupling of formate and H2 production in enterobacteria.
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Affiliation(s)
- Michelle Kammel
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle, Saale, Germany
| | - Christopher Erdmann
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle, Saale, Germany
| | - R Gary Sawers
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle, Saale, Germany.
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Kammel M, Pinske C, Sawers RG. FocA and its central role in fine-tuning pH homeostasis of enterobacterial formate metabolism. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36197793 DOI: 10.1099/mic.0.001253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
During enterobacterial mixed-acid fermentation, formate is generated from pyruvate by the glycyl-radical enzyme pyruvate formate-lyase (PflB). In Escherichia coli, especially at low pH, formate is then disproportionated to CO2 and H2 by the cytoplasmically oriented, membrane-associated formate hydrogenlyase (FHL) complex. If electron acceptors are available, however, formate is oxidized by periplasmically oriented, respiratory formate dehydrogenases. Formate translocation across the cytoplasmic membrane is controlled by the formate channel, FocA, a member of the formate-nitrite transporter (FNT) family of homopentameric anion channels. This review highlights recent advances in our understanding of how FocA helps to maintain intracellular formate and pH homeostasis during fermentation. Efflux and influx of formate/formic acid are distinct processes performed by FocA and both are controlled through protein interaction between FocA's N-terminal domain with PflB. Formic acid efflux by FocA helps to maintain cytoplasmic pH balance during exponential-phase growth. Uptake of formate against the electrochemical gradient (inside negative) is energetically and mechanistically challenging for a fermenting bacterium unless coupled with proton/cation symport. Translocation of formate/formic acid into the cytoplasm necessitates an active FHL complex, whose synthesis also depends on formate. Thus, FocA, FHL and PflB function together to govern formate homeostasis. We explain how FocA achieves efflux of formic acid and propose mechanisms for pH-dependent uptake of formate both with and without proton symport. We propose that FocA displays both channel- and transporter-like behaviour. Whether this translocation behaviour is shared by other members of the FNT family is also discussed.
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Affiliation(s)
- Michelle Kammel
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Constanze Pinske
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - R Gary Sawers
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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Metabolite Dysregulation by Pranlukast in Mycobacterium tuberculosis. Molecules 2022; 27:molecules27051520. [PMID: 35268621 PMCID: PMC8911922 DOI: 10.3390/molecules27051520] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/22/2021] [Accepted: 01/15/2022] [Indexed: 02/04/2023] Open
Abstract
Mycobacterium tuberculosis has been infecting millions of people worldwide over the years, causing tuberculosis. Drugs targeting distinct cellular mechanisms including synthesis of the cell wall, lipids, proteins, and nucleic acids in Mtb are currently being used for the treatment of TB. Although extensive research is being carried out at the molecular level in the infected host and pathogen, the identification of suitable drug targets and drugs remains under explored. Pranlukast, an allosteric inhibitor of MtArgJ (Mtb ornithine acetyltransferase) has previously been shown to inhibit the survival and virulence of Mtb. The main objective of this study was to identify the altered metabolic pathways and biological processes associated with the differentially expressed metabolites by PRK in Mtb. Here in this study, metabolomics was carried out using an LC-MS/MS-based approach. Collectively, 50 metabolites were identified to be differentially expressed with a significant p-value through a global metabolomic approach using a high-resolution mass spectrometer. Metabolites downstream of argJ were downregulated in the arginine biosynthetic pathway following pranlukast treatment. Predicted human protein interactors of pranlukast-treated Mtb metabolome were identified in association with autophagy, inflammation, DNA repair, and other immune-related processes. Further metabolites including N-acetylglutamate, argininosuccinate, L-arginine, succinate, ergothioneine, and L-phenylalanine were validated by multiple reaction monitoring, a targeted mass spectrometry-based metabolomic approach. This study facilitates the understanding of pranlukast-mediated metabolic changes in Mtb and holds the potential to identify novel therapeutic approaches using metabolic pathways in Mtb.
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Mishra A, Mamidi AS, Rajmani RS, Ray A, Roy R, Surolia A. An allosteric inhibitor of Mycobacterium tuberculosis ArgJ: Implications to a novel combinatorial therapy. EMBO Mol Med 2019; 10:emmm.201708038. [PMID: 29483133 PMCID: PMC5887547 DOI: 10.15252/emmm.201708038] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The existing treatment regime against tuberculosis is not adequate, and novel therapeutic interventions are required to target Mycobacterium tuberculosis (Mtb) pathogenesis. We report Pranlukast (PRK) as a novel allosteric inhibitor of Mtb's arginine biosynthetic enzyme, Ornithine acetyltransferase (MtArgJ). PRK treatment remarkably abates the survival of free as well as macrophage‐internalized Mtb, and shows enhanced efficacy in combination with standard‐of‐care drugs. Notably, PRK also reduces the 5‐lipoxygenase (5‐LO) signaling in the infected macrophages, thereby surmounting an enhanced response against intracellular pathogen. Further, treatment with PRK alone or with rifampicin leads to significant decrease in Mtb burden and tubercular granulomas in Mtb‐infected mice lungs. Taken together, this study demonstrates a novel allosteric inhibitor of MtArgJ, which acts as a dual‐edged sword, by targeting the intracellular bacteria as well as the bacterial pro‐survival signaling in the host. PRK is highly effective against in vitro and in vivo survival of Mtb and being an FDA‐approved drug, it shows a potential for development of advanced combinatorial therapy against tuberculosis.
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Affiliation(s)
- Archita Mishra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Ashalatha S Mamidi
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Raju S Rajmani
- Microbiology and Cell Biology, CIDR, Indian Institute of Science, Bangalore, India
| | - Ananya Ray
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Rajanya Roy
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Avadhesha Surolia
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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Feng R, Sun G, Zhang Y, Sun Q, Ju L, Sun C, Wang C. Short-term high-fat diet exacerbates insulin resistance and glycolipid metabolism disorders in young obese men with hyperlipidemia, as determined by metabolomics analysis using ultra-HPLC-quadrupole time-of-flight mass spectrometry. J Diabetes 2019; 11:148-160. [PMID: 30058212 DOI: 10.1111/1753-0407.12828] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/24/2018] [Accepted: 07/24/2018] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The prevalence of obesity is increasing rapidly worldwide, and dietary intake is strongly associated with obesity-related chronic diseases. However, key metabolic perturbations in obese young men with hyperlipidemia after high-fat diet (HFD) intervention are not yet clear, and remain to be determined. The aim of this study was to investigate the effects of a short-term HFD on glycolipid metabolism, insulin resistance (IR), and urinary metabolomic profiling in young obese men with hyperlipidemia. METHODS Sixty young men (19-25 years; 30 normal weight, 30 obese with hyperlipidemia) were enrolled in the study. Differences in metabolomic profiling of urine between normal-weight and obese young men before and after 3 days intake of the HFD were investigated using ultra-HPLC-quadrupole time-of-flight mass spectrometry. RESULTS After the HFD intervention, total cholesterol (TC), low-density lipoprotein cholesterol, fasting plasma glucose, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) were significantly increased and high-density lipoprotein cholesterol was significantly decreased in obese men, but only TC was significantly increased in normal-weight subjects. Based on metabolic differences, normal-weight and obese men, and obese men before and after the HFD intervention could be separated into distinct clusters. Seventeen major metabolites were identified that were associated with type 2 diabetes mellitus, glycolipid metabolism and IR; the changes in these metabolites suggest metabolic changes in young obese males after short-term HFD intake. CONCLUSIONS The findings of this study may contribute to increased understanding of the early biological adaptations of obesity with hyperlipidemia to HFD for the early prevention and control of diabetes and IR.
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Affiliation(s)
- Rennan Feng
- Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, Harbin, China
| | - Guozhang Sun
- Department of Neurosurgery, Heilongjiang Provincial Hospital, Harbin, China
| | - Yunbo Zhang
- Department of Environmental Hygiene, Public Health College, Harbin Medical University, Harbin, China
| | - Qintong Sun
- Department of Environmental Hygiene, Public Health College, Harbin Medical University, Harbin, China
| | - Liyan Ju
- Department of Laboratory, Harbin Center for Disease Control and Prevention, Harbin, China
| | - Changhao Sun
- Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, Harbin, China
| | - Cheng Wang
- Department of Environmental Hygiene, Public Health College, Harbin Medical University, Harbin, China
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Zhou J, Zhang R, Yang T, Liu Q, Zheng J, Wang F, Liu F, Xu M, Zhang X, Rao Z. Relieving Allosteric Inhibition by Designing Active Inclusion Bodies and Coating of the Inclusion Bodies with Fe3O4 Nanomaterials for Sustainable 2-Oxobutyric Acid Production. ACS Catal 2018. [DOI: 10.1021/acscatal.8b03181] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Junping Zhou
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Rongzhen Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Taowei Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Qiaoli Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Junxian Zheng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Fang Wang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Fei Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Meijuan Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Xian Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Zhiming Rao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
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Structural basis of the correct subunit assembly, aggregation, and intracellular degradation of nylon hydrolase. Sci Rep 2018; 8:9725. [PMID: 29950566 PMCID: PMC6021441 DOI: 10.1038/s41598-018-27860-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 06/12/2018] [Indexed: 11/09/2022] Open
Abstract
Nylon hydrolase (NylC) is initially expressed as an inactive precursor (36 kDa). The precursor is cleaved autocatalytically at Asn266/Thr267 to generate an active enzyme composed of an α subunit (27 kDa) and a β subunit (9 kDa). Four αβ heterodimers (molecules A-D) form a doughnut-shaped quaternary structure. In this study, the thermostability of the parental NylC was altered by amino acid substitutions located at the A/D interface (D122G/H130Y/D36A/L137A) or the A/B interface (E263Q) and spanned a range of 47 °C. Considering structural, biophysical, and biochemical analyses, we discuss the structural basis of the stability of nylon hydrolase. From the analytical centrifugation data obtained regarding the various mutant enzymes, we conclude that the assembly of the monomeric units is dynamically altered by the mutations. Finally, we propose a model that can predict whether the fate of the nascent polypeptide will be correct subunit assembly, inappropriate protein-protein interactions causing aggregation, or intracellular degradation of the polypeptide.
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Shu Q, Xu M, Li J, Yang T, Zhang X, Xu Z, Rao Z. Improved l-ornithine production in Corynebacterium crenatum by introducing an artificial linear transacetylation pathway. ACTA ACUST UNITED AC 2018; 45:393-404. [DOI: 10.1007/s10295-018-2037-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 04/23/2018] [Indexed: 01/14/2023]
Abstract
Abstract
l-Ornithine is a non-protein amino acid with extensive applications in the food and pharmaceutical industries. In this study, we performed metabolic pathway engineering of an l-arginine hyper-producing strain of Corynebacterium crenatum for L-ornithine production. First, we amplified the L-ornithine biosynthetic pathway flux by blocking the competing branch of the pathway. To enhance L-ornithine synthesis, we performed site-directed mutagenesis of the ornithine-binding sites to solve the problem of l-ornithine feedback inhibition for ornithine acetyltransferase. Alternatively, the genes argA from Escherichia coli and argE from Serratia marcescens, encoding the enzymes N-acetyl glutamate synthase and N-acetyl-l-ornithine deacetylase, respectively, were introduced into Corynebacterium crenatum to mimic the linear pathway of L-ornithine biosynthesis. Fermentation of the resulting strain in a 5-L bioreactor allowed a dramatically increased production of L-ornithine, 40.4 g/L, with an overall productivity of 0.673 g/L/h over 60 h. This demonstrates that an increased level of transacetylation is beneficial for L-ornithine biosynthesis.
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Affiliation(s)
- Qunfeng Shu
- 0000 0001 0708 1323 grid.258151.a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi Jiangsu People’s Republic of China
| | - Meijuan Xu
- 0000 0001 0708 1323 grid.258151.a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi Jiangsu People’s Republic of China
| | - Jing Li
- 0000 0001 0708 1323 grid.258151.a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi Jiangsu People’s Republic of China
| | - Taowei Yang
- 0000 0001 0708 1323 grid.258151.a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi Jiangsu People’s Republic of China
| | - Xian Zhang
- 0000 0001 0708 1323 grid.258151.a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi Jiangsu People’s Republic of China
| | - Zhenghong Xu
- 0000 0001 0708 1323 grid.258151.a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi Jiangsu People’s Republic of China
| | - Zhiming Rao
- 0000 0001 0708 1323 grid.258151.a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi Jiangsu People’s Republic of China
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Shi D, Allewell NM, Tuchman M. From Genome to Structure and Back Again: A Family Portrait of the Transcarbamylases. Int J Mol Sci 2015; 16:18836-64. [PMID: 26274952 PMCID: PMC4581275 DOI: 10.3390/ijms160818836] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 11/18/2022] Open
Abstract
Enzymes in the transcarbamylase family catalyze the transfer of a carbamyl group from carbamyl phosphate (CP) to an amino group of a second substrate. The two best-characterized members, aspartate transcarbamylase (ATCase) and ornithine transcarbamylase (OTCase), are present in most organisms from bacteria to humans. Recently, structures of four new transcarbamylase members, N-acetyl-l-ornithine transcarbamylase (AOTCase), N-succinyl-l-ornithine transcarbamylase (SOTCase), ygeW encoded transcarbamylase (YTCase) and putrescine transcarbamylase (PTCase) have also been determined. Crystal structures of these enzymes have shown that they have a common overall fold with a trimer as their basic biological unit. The monomer structures share a common CP binding site in their N-terminal domain, but have different second substrate binding sites in their C-terminal domain. The discovery of three new transcarbamylases, l-2,3-diaminopropionate transcarbamylase (DPTCase), l-2,4-diaminobutyrate transcarbamylase (DBTCase) and ureidoglycine transcarbamylase (UGTCase), demonstrates that our knowledge and understanding of the spectrum of the transcarbamylase family is still incomplete. In this review, we summarize studies on the structures and function of transcarbamylases demonstrating how structural information helps to define biological function and how small structural differences govern enzyme specificity. Such information is important for correctly annotating transcarbamylase sequences in the genome databases and for identifying new members of the transcarbamylase family.
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Affiliation(s)
- Dashuang Shi
- Center for Genetic Medicine Research, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA.
- Department of Integrative Systems Biology, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA.
| | - Norma M Allewell
- Department of Cell Biology and Molecular Genetics, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20742, USA.
- Department of Chemistry and Biochemistry, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20742, USA.
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA.
- Department of Integrative Systems Biology, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA.
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The N-Acetylglutamate Synthase Family: Structures, Function and Mechanisms. Int J Mol Sci 2015; 16:13004-22. [PMID: 26068232 PMCID: PMC4490483 DOI: 10.3390/ijms160613004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/24/2015] [Accepted: 05/13/2015] [Indexed: 11/17/2022] Open
Abstract
N-acetylglutamate synthase (NAGS) catalyzes the production of N-acetylglutamate (NAG) from acetyl-CoA and l-glutamate. In microorganisms and plants, the enzyme functions in the arginine biosynthetic pathway, while in mammals, its major role is to produce the essential co-factor of carbamoyl phosphate synthetase 1 (CPS1) in the urea cycle. Recent work has shown that several different genes encode enzymes that can catalyze NAG formation. A bifunctional enzyme was identified in certain bacteria, which catalyzes both NAGS and N-acetylglutamate kinase (NAGK) activities, the first two steps of the arginine biosynthetic pathway. Interestingly, these bifunctional enzymes have higher sequence similarity to vertebrate NAGS than those of the classical (mono-functional) bacterial NAGS. Solving the structures for both classical bacterial NAGS and bifunctional vertebrate-like NAGS/K has advanced our insight into the regulation and catalytic mechanisms of NAGS, and the evolutionary relationship between the two NAGS groups.
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Abstract
Rhizobia are bacteria in the α-proteobacterial genera Rhizobium, Sinorhizobium, Mesorhizobium, Azorhizobium and Bradyrhizobium that reduce (fix) atmospheric nitrogen in symbiotic association with a compatible host plant. In free-living and/or symbiotically associated rhizobia, amino acids may, in addition to their incorporation into proteins, serve as carbon, nitrogen or sulfur sources, signals of cellular nitrogen status and precursors of important metabolites. Depending on the rhizobia-host plant combination, microsymbiont amino acid metabolism (biosynthesis, transport and/or degradation) is often crucial to the establishment and maintenance of an effective nitrogen-fixing symbiosis and is intimately interconnected with the metabolism of the plant. This review summarizes past findings and current research directions in rhizobial amino acid metabolism and evaluates the genetic, biochemical and genome expression studies from which these are derived. Specific sections deal with the regulation of rhizobial amino acid metabolism, amino acid transport, and finally the symbiotic roles of individual amino acids in different plant-rhizobia combinations.
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12
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Hamed RB, Gomez-Castellanos JR, Henry L, Ducho C, McDonough MA, Schofield CJ. The enzymes of β-lactam biosynthesis. Nat Prod Rep 2013; 30:21-107. [DOI: 10.1039/c2np20065a] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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13
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Negoro S, Shibata N, Tanaka Y, Yasuhira K, Shibata H, Hashimoto H, Lee YH, Oshima S, Santa R, Oshima S, Mochiji K, Goto Y, Ikegami T, Nagai K, Kato DI, Takeo M, Higuchi Y. Three-dimensional structure of nylon hydrolase and mechanism of nylon-6 hydrolysis. J Biol Chem 2011; 287:5079-90. [PMID: 22187439 DOI: 10.1074/jbc.m111.321992] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We performed x-ray crystallographic analyses of the 6-aminohexanoate oligomer hydrolase (NylC) from Agromyces sp. at 2.0 Å-resolution. This enzyme is a member of the N-terminal nucleophile hydrolase superfamily that is responsible for the degradation of the nylon-6 industry byproduct. We observed four identical heterodimers (27 kDa + 9 kDa), which resulted from the autoprocessing of the precursor protein (36 kDa) and which constitute the doughnut-shaped quaternary structure. The catalytic residue of NylC was identified as the N-terminal Thr-267 of the 9-kDa subunit. Furthermore, each heterodimer is folded into a single domain, generating a stacked αββα core structure. Amino acid mutations at subunit interfaces of the tetramer were observed to drastically alter the thermostability of the protein. In particular, four mutations (D122G/H130Y/D36A/E263Q) of wild-type NylC from Arthrobacter sp. (plasmid pOAD2-encoding enzyme), with a heat denaturation temperature of T(m) = 52 °C, enhanced the protein thermostability by 36 °C (T(m) = 88 °C), whereas a single mutation (G111S or L137A) decreased the stability by ∼10 °C. We examined the enzymatic hydrolysis of nylon-6 by the thermostable NylC mutant. Argon cluster secondary ion mass spectrometry analyses of the reaction products revealed that the major peak of nylon-6 (m/z 10,000-25,000) shifted to a smaller range, producing a new peak corresponding to m/z 1500-3000 after the enzyme treatment at 60 °C. In addition, smaller fragments in the soluble fraction were successively hydrolyzed to dimers and monomers. Based on these data, we propose that NylC should be designated as nylon hydrolase (or nylonase). Three potential uses of NylC for industrial and environmental applications are also discussed.
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Affiliation(s)
- Seiji Negoro
- Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, Hyogo 671-2280
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Iqbal A, Clifton IJ, Chowdhury R, Ivison D, Domene C, Schofield CJ. Structural and biochemical analyses reveal how ornithine acetyl transferase binds acidic and basic amino acid substrates. Org Biomol Chem 2011; 9:6219-25. [PMID: 21796301 DOI: 10.1039/c1ob05554b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural and biochemical analyses reveal how ornithine acetyl-transferases catalyse the reversible transfer of an acetyl-group from a basic (ornithine) to an acidic (glutamate) amino acid by employing a common mechanism involving an acetyl-enzyme intermediate but using different side chain binding modes.
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Affiliation(s)
- Aman Iqbal
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
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15
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Chim N, Habel JE, Johnston JM, Krieger I, Miallau L, Sankaranarayanan R, Morse RP, Bruning J, Swanson S, Kim H, Kim CY, Li H, Bulloch EM, Payne RJ, Manos-Turvey A, Hung LW, Baker EN, Lott JS, James MNG, Terwilliger TC, Eisenberg DS, Sacchettini JC, Goulding CW. The TB Structural Genomics Consortium: a decade of progress. Tuberculosis (Edinb) 2011; 91:155-72. [PMID: 21247804 DOI: 10.1016/j.tube.2010.11.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 11/19/2010] [Accepted: 11/26/2010] [Indexed: 01/03/2023]
Abstract
The TB Structural Genomics Consortium is a worldwide organization of collaborators whose mission is the comprehensive structural determination and analyses of Mycobacterium tuberculosis proteins to ultimately aid in tuberculosis diagnosis and treatment. Congruent to the overall vision, Consortium members have additionally established an integrated facilities core to streamline M. tuberculosis structural biology and developed bioinformatics resources for data mining. This review aims to share the latest Consortium developments with the TB community, including recent structures of proteins that play significant roles within M. tuberculosis. Atomic resolution details may unravel mechanistic insights and reveal unique and novel protein features, as well as important protein-protein and protein-ligand interactions, which ultimately lead to a better understanding of M. tuberculosis biology and may be exploited for rational, structure-based therapeutics design.
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Affiliation(s)
- Nicholas Chim
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
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