1
|
Zhao JR, Zuo SQ, Xiao F, Guo FZ, Chen LY, Bi K, Cheng DY, Xu ZN. Advances in biotin biosynthesis and biotechnological production in microorganisms. World J Microbiol Biotechnol 2024; 40:163. [PMID: 38613659 DOI: 10.1007/s11274-024-03971-7] [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: 02/01/2024] [Accepted: 03/28/2024] [Indexed: 04/15/2024]
Abstract
Biotin, also known as vitamin H or B7, acts as a crucial cofactor in the central metabolism processes of fatty acids, amino acids, and carbohydrates. Biotin has important applications in food additives, biomedicine, and other fields. While the ability to synthesize biotin de novo is confined to microorganisms and plants, humans and animals require substantial daily intake, primarily through dietary sources and intestinal microflora. Currently, chemical synthesis stands as the primary method for commercial biotin production, although microbial biotin production offers an environmentally sustainable alternative with promising prospects. This review presents a comprehensive overview of the pathways involved in de novo biotin synthesis in various species of microbes and insights into its regulatory and transport systems. Furthermore, diverse strategies are discussed to improve the biotin production here, including mutation breeding, rational metabolic engineering design, artificial genetic modification, and process optimization. The review also presents the potential strategies for addressing current challenges for industrial-scale bioproduction of biotin in the future. This review is very helpful for exploring efficient and sustainable strategies for large-scale biotin production.
Collapse
Affiliation(s)
- Jia-Run Zhao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- Institute of Biological Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Si-Qi Zuo
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- Institute of Biological Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Feng Xiao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- Institute of Biological Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 310000, China
| | - Feng-Zhu Guo
- Zhejiang Sliver-Elephant Bio-engineering Co., Ltd., Tiantai, 317200, China
| | - Lu-Yi Chen
- Zhejiang Sliver-Elephant Bio-engineering Co., Ltd., Tiantai, 317200, China
| | - Ke Bi
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- Institute of Biological Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Dong-Yuan Cheng
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- Institute of Biological Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zhi-Nan Xu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
- Institute of Biological Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
| |
Collapse
|
2
|
Othman D, Elhosseiny NM, Eltayeb WN, Attia AS. The Moraxella catarrhalis AdhC-FghA system is important for formaldehyde detoxification and protection against pulmonary clearance. Med Microbiol Immunol 2024; 213:3. [PMID: 38448747 PMCID: PMC10917845 DOI: 10.1007/s00430-024-00785-0] [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: 10/21/2023] [Accepted: 01/24/2024] [Indexed: 03/08/2024]
Abstract
Multidrug-resistant clinical isolates of Moraxella catarrhalis have emerged, increasing the demand for the identification of new treatment and prevention strategies. A thorough understanding of how M. catarrhalis can establish an infection and respond to different stressors encountered in the host is crucial for new drug-target identification. Formaldehyde is a highly cytotoxic compound that can be produced endogenously as a by-product of metabolism and exogenously from environmental sources. Pathways responsible for formaldehyde detoxification are thus essential and are found in all domains of life. The current work investigated the role of the system consisting of the S-hydroxymethyl alcohol dehydrogenase (AdhC), a Zn-dependent class III alcohol dehydrogenase, and the S-formyl glutathione hydrolase (FghA) in the formaldehyde detoxification process in M. catarrhalis. Bioinformatics showed that the components of the system are conserved across the species and are highly similar to those of Streptococcus pneumoniae, which share the same biological niche. Isogenic mutants were constructed to study the function of the system in M. catarrhalis. A single fghA knockout mutant did not confer sensitivity to formaldehyde, while the adhC-fghA double mutant is formaldehyde-sensitive. In addition, both mutants were significantly cleared in a murine pulmonary model of infection as compared to the wild type, demonstrating the system's importance for this pathogen's virulence. The respective phenotypes were reversed upon the genetic complementation of the mutants. To date, this is the first study investigating the role of the AdhC-FghA system in formaldehyde detoxification and pathogenesis of M. catarrhalis.
Collapse
Affiliation(s)
- Dina Othman
- Graduate Program, Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt
| | - Noha M Elhosseiny
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Room #D404, Kasr El-Ainy Street, Cairo, 11562, Egypt
| | - Wafaa N Eltayeb
- Department of Microbiology, Faculty of Pharmacy, Misr International University, Cairo, 19648, Egypt
| | - Ahmed S Attia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Room #D404, Kasr El-Ainy Street, Cairo, 11562, Egypt.
| |
Collapse
|
3
|
Shi Y, Cao Q, Sun J, Hu X, Su Z, Xu Y, Zhang H, Lan L, Feng Y. The opportunistic pathogen Pseudomonas aeruginosa exploits bacterial biotin synthesis pathway to benefit its infectivity. PLoS Pathog 2023; 19:e1011110. [PMID: 36689471 PMCID: PMC9894557 DOI: 10.1371/journal.ppat.1011110] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 02/02/2023] [Accepted: 01/09/2023] [Indexed: 01/24/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that predominantly causes nosocomial and community-acquired lung infections. As a member of ESKAPE pathogens, carbapenem-resistant P. aeruginosa (CRPA) compromises the limited therapeutic options, raising an urgent demand for the development of lead compounds against previously-unrecognized drug targets. Biotin is an important cofactor, of which the de novo synthesis is an attractive antimicrobial target in certain recalcitrant infections. Here we report genetic and biochemical definition of P. aeruginosa BioH (PA0502) that functions as a gatekeeper enzyme allowing the product pimeloyl-ACP to exit from fatty acid synthesis cycle and to enter the late stage of biotin synthesis pathway. In relative to Escherichia coli, P. aeruginosa physiologically requires 3-fold higher level of cytosolic biotin, which can be attributed to the occurrence of multiple biotinylated enzymes. The BioH protein enables the in vitro reconstitution of biotin synthesis. The repertoire of biotin abundance is assigned to different mouse tissues and/or organ contents, and the plasma biotin level of mouse is around 6-fold higher than that of human. Removal of bioH renders P. aeruginosa biotin auxotrophic and impairs its intra-phagosome persistence. Based on a model of CD-1 mice mimicking the human environment, lung challenge combined with systemic infection suggested that BioH is necessary for the full virulence of P. aeruginosa. As expected, the biotin synthesis inhibitor MAC13772 is capable of dampening the viability of CRPA. Notably, MAC13772 interferes the production of pyocyanin, an important virulence factor of P. aeruginosa. Our data expands our understanding of P. aeruginosa biotin synthesis relevant to bacterial infectivity. In particular, this study represents the first example of an extracellular pathogen P. aeruginosa that exploits biotin cofactor as a fitness determinant, raising the possibility of biotin synthesis as an anti-CRPA target.
Collapse
Affiliation(s)
- Yu Shi
- Department of Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Qin Cao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
| | - Jingdu Sun
- Department of Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaofang Hu
- Fuzhou Medical College of Nanchang University, Fuzhou, Jiangxi, China
| | - Zhi Su
- Department of Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Yongchang Xu
- Department of Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Huimin Zhang
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Lefu Lan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- * E-mail: (LL); (YF)
| | - Youjun Feng
- Department of Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
- * E-mail: (LL); (YF)
| |
Collapse
|
4
|
Xu Y, Yang J, Li W, Song S, Shi Y, Wu L, Sun J, Hou M, Wang J, Jia X, Zhang H, Huang M, Lu T, Gan J, Feng Y. Three enigmatic BioH isoenzymes are programmed in the early stage of mycobacterial biotin synthesis, an attractive anti-TB drug target. PLoS Pathog 2022; 18:e1010615. [PMID: 35816546 PMCID: PMC9302846 DOI: 10.1371/journal.ppat.1010615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/21/2022] [Accepted: 05/24/2022] [Indexed: 11/19/2022] Open
Abstract
Tuberculosis (TB) is one of the leading infectious diseases of global concern, and one quarter of the world’s population are TB carriers. Biotin metabolism appears to be an attractive anti-TB drug target. However, the first-stage of mycobacterial biotin synthesis is fragmentarily understood. Here we report that three evolutionarily-distinct BioH isoenzymes (BioH1 to BioH3) are programmed in biotin synthesis of Mycobacterium smegmatis. Expression of an individual bioH isoform is sufficient to allow the growth of an Escherichia coli ΔbioH mutant on the non-permissive condition lacking biotin. The enzymatic activity in vitro combined with biotin bioassay in vivo reveals that BioH2 and BioH3 are capable of removing methyl moiety from pimeloyl-ACP methyl ester to give pimeloyl-ACP, a cognate precursor for biotin synthesis. In particular, we determine the crystal structure of dimeric BioH3 at 2.27Å, featuring a unique lid domain. Apart from its catalytic triad, we also dissect the substrate recognition of BioH3 by pimeloyl-ACP methyl ester. The removal of triple bioH isoforms (ΔbioH1/2/3) renders M. smegmatis biotin auxotrophic. Along with the newly-identified Tam/BioC, the discovery of three unusual BioH isoforms defines an atypical ‘BioC-BioH(3)’ paradigm for the first-stage of mycobacterial biotin synthesis. This study solves a long-standing puzzle in mycobacterial nutritional immunity, providing an alternative anti-TB drug target.
Collapse
Affiliation(s)
- Yongchang Xu
- Departments of Microbiology, and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, The People’s Republic of China
| | - Jie Yang
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Science, Fudan University, Shanghai, The People’s Republic of China
| | - Weihui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, The People’s Republic of China
| | - Shuaijie Song
- Departments of Microbiology, and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, The People’s Republic of China
| | - Yu Shi
- Departments of Microbiology, and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, The People’s Republic of China
| | - Lihan Wu
- Departments of Microbiology, and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, The People’s Republic of China
| | - Jingdu Sun
- Departments of Microbiology, and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, The People’s Republic of China
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, The People’s Republic of China
| | - Mengyun Hou
- Departments of Microbiology, and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, The People’s Republic of China
| | - Jinzi Wang
- Guangxi Key Laboratory of Utilization of Microbial and Botanical Resources & Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi Minzu University, Nanning, Guangxi, The People’s Republic of China
| | - Xu Jia
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, Sichuan, The People’s Republic of China
| | - Huimin Zhang
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Man Huang
- Departments of Microbiology, and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, The People’s Republic of China
| | - Ting Lu
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Jianhua Gan
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Science, Fudan University, Shanghai, The People’s Republic of China
- * E-mail: (JG); (YF)
| | - Youjun Feng
- Departments of Microbiology, and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, The People’s Republic of China
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, The People’s Republic of China
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, Sichuan, The People’s Republic of China
- * E-mail: (JG); (YF)
| |
Collapse
|
5
|
Song X, Cronan JE. A conserved and seemingly redundant Escherichia coli biotin biosynthesis gene expressed only during anaerobic growth. Mol Microbiol 2021; 116:1315-1327. [PMID: 34597430 PMCID: PMC8599648 DOI: 10.1111/mmi.14826] [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: 08/23/2021] [Revised: 09/26/2021] [Accepted: 09/27/2021] [Indexed: 11/30/2022]
Abstract
Biotin is an essential metabolic cofactor and de novo biotin biosynthetic pathways are widespread in microorganisms and plants. Biotin synthetic genes are generally found clustered into bio operons to facilitate tight regulation since biotin synthesis is a metabolically expensive process. Dethiobiotin synthetase (DTBS) catalyzes the penultimate step of biotin biosynthesis, the formation of 7,8-diaminononanoate (DAPA). In Escherichia coli, DTBS is encoded by the bio operon gene bioD. Several studies have reported transcriptional activation of ynfK a gene of unknown function, under anaerobic conditions. Alignments of YnfK with BioD have led to suggestions that YnfK has DTBS activity. We report that YnfK is a functional DTBS, although an enzyme of poor activity that is poorly expressed. Supplementation of growth medium with DAPA or substitution of BioD active site residues for the corresponding YnfK residues greatly improved the DTBS activity of YnfK. We confirmed that FNR activates transcriptional level of ynfK during anaerobic growth and identified the FNR binding site of ynfK. The ynfK gene is well conserved in γ-proteobacteria.
Collapse
Affiliation(s)
- Xuejiao Song
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
| | - John E Cronan
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
| |
Collapse
|
6
|
Sirithanakorn C, Cronan JE. Biotin, a universal and essential cofactor: Synthesis, ligation and regulation. FEMS Microbiol Rev 2021; 45:6081095. [PMID: 33428728 DOI: 10.1093/femsre/fuab003] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/08/2021] [Indexed: 12/22/2022] Open
Abstract
Biotin is a covalently attached enzyme cofactor required for intermediary metabolism in all three domains of life. Several important human pathogens (e.g. Mycobacterium tuberculosis) require biotin synthesis for pathogenesis. Humans lack a biotin synthetic pathway hence bacterial biotin synthesis is a prime target for new therapeutic agents. The biotin synthetic pathway is readily divided into early and late segments. Although pimelate, a seven carbon α,ω-dicarboxylic acid that contributes seven of the ten biotin carbons atoms, was long known to be a biotin precursor, its biosynthetic pathway was a mystery until the E. coli pathway was discovered in 2010. Since then, diverse bacteria encode evolutionarily distinct enzymes that replace enzymes in the E. coli pathway. Two new bacterial pimelate synthesis pathways have been elucidated. In contrast to the early pathway the late pathway, assembly of the fused rings of the cofactor, was long thought settled. However, a new enzyme that bypasses a canonical enzyme was recently discovered as well as homologs of another canonical enzyme that functions in synthesis of another protein-bound coenzyme, lipoic acid. Most bacteria tightly regulate transcription of the biotin synthetic genes in a biotin-responsive manner. The bifunctional biotin ligases which catalyze attachment of biotin to its cognate enzymes and repress biotin gene transcription are best understood regulatory system.
Collapse
Affiliation(s)
- Chaiyos Sirithanakorn
- Faculty of Medicine, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand.,Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
| | - John E Cronan
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.,Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| |
Collapse
|
7
|
Driscoll TP, Verhoeve VI, Brockway C, Shrewsberry DL, Plumer M, Sevdalis SE, Beckmann JF, Krueger LM, Macaluso KR, Azad AF, Gillespie JJ. Evolution of Wolbachia mutualism and reproductive parasitism: insight from two novel strains that co-infect cat fleas. PeerJ 2020; 8:e10646. [PMID: 33362982 PMCID: PMC7750005 DOI: 10.7717/peerj.10646] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/03/2020] [Indexed: 12/26/2022] Open
Abstract
Wolbachiae are obligate intracellular bacteria that infect arthropods and certain nematodes. Usually maternally inherited, they may provision nutrients to (mutualism) or alter sexual biology of (reproductive parasitism) their invertebrate hosts. We report the assembly of closed genomes for two novel wolbachiae, wCfeT and wCfeJ, found co-infecting cat fleas (Ctenocephalides felis) of the Elward Laboratory colony (Soquel, CA, USA). wCfeT is basal to nearly all described Wolbachia supergroups, while wCfeJ is related to supergroups C, D and F. Both genomes contain laterally transferred genes that inform on the evolution of Wolbachia host associations. wCfeT carries the Biotin synthesis Operon of Obligate intracellular Microbes (BOOM); our analyses reveal five independent acquisitions of BOOM across the Wolbachia tree, indicating parallel evolution towards mutualism. Alternately, wCfeJ harbors a toxin-antidote operon analogous to the wPip cinAB operon recently characterized as an inducer of cytoplasmic incompatibility (CI) in flies. wCfeJ cinB and three adjacent genes are collectively similar to large modular toxins encoded in CI-like operons of certain Wolbachia strains and Rickettsia species, signifying that CI toxins streamline by fission of large modular toxins. Remarkably, the C. felis genome itself contains two CI-like antidote genes, divergent from wCfeJ cinA, revealing episodic reproductive parasitism in cat fleas and evidencing mobility of CI loci independent of WO-phage. Additional screening revealed predominant co-infection (wCfeT/wCfeJ) amongst C. felis colonies, though fleas in wild populations mostly harbor wCfeT alone. Collectively, genomes of wCfeT, wCfeJ, and their cat flea host supply instances of lateral gene transfers that could drive transitions between parasitism and mutualism.
Collapse
Affiliation(s)
| | - Victoria I Verhoeve
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| | | | | | - Mariah Plumer
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| | - Spiridon E Sevdalis
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| | - John F Beckmann
- Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Laura M Krueger
- Orange County Mosquito and Vector Control District, Garden Grove, CA, USA
| | - Kevin R Macaluso
- Microbiology and Immunology, University of South Alabama, Mobile, AL, USA
| | - Abdu F Azad
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| | - Joseph J Gillespie
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| |
Collapse
|
8
|
Abstract
Biotin plays an essential role in growth of mycobacteria. Synthesis of the cofactor is essential for Mycobacterium tuberculosis to establish and maintain chronic infections in a murine model of tuberculosis. Although the late steps of mycobacterial biotin synthesis, assembly of the heterocyclic rings, are thought to follow the canonical pathway, the mechanism of synthesis of the pimelic acid moiety that contributes most of the biotin carbon atoms is unknown. We report that the Mycobacterium smegmatis gene annotated as encoding Tam, an O-methyltransferase that monomethylates and detoxifies trans-aconitate, instead encodes a protein having the activity of BioC, an O-methyltransferase that methylates the free carboxyl of malonyl-ACP. The M. smegmatis Tam functionally replaced Escherichia coli BioC both in vivo and in vitro. Moreover, deletion of the M. smegmatis tam gene resulted in biotin auxotrophy, and addition of biotin to M. smegmatis cultures repressed tam gene transcription. Although its pathogenicity precluded in vivo studies, the M. tuberculosis Tam also replaced E. coli BioC both in vivo and in vitro and complemented biotin-independent growth of the M. smegmatis tam deletion mutant strain. Based on these data, we propose that the highly conserved mycobacterial tam genes be renamed bioCM. tuberculosis BioC presents a target for antituberculosis drugs which thus far have been directed at late reactions in the pathway with some success.
Collapse
Affiliation(s)
- Zhe Hu
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - John E Cronan
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| |
Collapse
|