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Chauhan P, Datta I, Dhiman A, Shankar U, Kumar A, Vashist A, Sharma TK, Tyagi JS. DNA Aptamer Targets Mycobacterium tuberculosis DevR/DosR Response Regulator Function by Inhibiting Its Dimerization and DNA Binding Activity. ACS Infect Dis 2022; 8:2540-2551. [PMID: 36332135 DOI: 10.1021/acsinfecdis.2c00414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tuberculosis is recognized as one of the major public health threats worldwide. The DevR-DevS (DosR/DosS) two-component system is considered a novel drug target in Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis, owing to its central role in bacterial adaptation and long-term persistence. An increase in DevR levels and the decreased permeability of the mycobacterial cell wall during hypoxia-associated dormancy pose formidable challenges to the development of anti-DevR compounds. Using an in vitro evolution approach of Systematic Evolution of Ligands by EXponential enrichment (SELEX), we developed a panel of single-stranded DNA aptamers that interacted with Mtb DevR protein in solid-phase binding assays. The best-performing aptamer, APT-6, forms a G-quadruplex structure and inhibits DevR-dependent transcription in Mycobacterium smegmatis. Mechanistic studies indicate that APT-6 functions by inhibiting the dimerization and DNA binding activity of DevR protein. In silico studies reveal that APT-6 interacts majorly with C-terminal domain residues that participate in DNA binding and formation of active dimer species of DevR. To the best of our knowledge, this is the first report of a DNA aptamer that inhibits the function of a cytosolic bacterial response regulator. By inhibiting the dimerization of DevR, APT-6 targets an essential step in the DevR activation mechanism, and therefore, it has the potential to universally block the expression of DevR-regulated genes for intercepting dormancy pathways in mycobacteria. These findings also pave the way for exploring aptamer-based approaches to design and develop potent inhibitors against intracellular proteins of various bacterial pathogens of global concern.
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Affiliation(s)
- Priyanka Chauhan
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Ishara Datta
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Abhijeet Dhiman
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Uma Shankar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore453552, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore453552, India
| | - Atul Vashist
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Tarun Kumar Sharma
- Translational Health Science and Technology Institute (THSTI), Faridabad, Haryana121001, India
| | - Jaya Sivaswami Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
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2
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Schumann NC, Lee KJ, Thompson AP, Salaemae W, Pederick JL, Avery T, Gaiser BI, Hodgkinson-Bean J, Booker GW, Polyak SW, Bruning JB, Wegener KL, Abell AD. Inhibition of Mycobacterium tuberculosis Dethiobiotin Synthase ( MtDTBS): Toward Next-Generation Antituberculosis Agents. ACS Chem Biol 2021; 16:2339-2347. [PMID: 34533923 DOI: 10.1021/acschembio.1c00491] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mycobacterium tuberculosis dethiobiotin synthase (MtDTBS) is a crucial enzyme involved in the biosynthesis of biotin in the causative agent of tuberculosis, M. tuberculosis. Here, we report a binder of MtDTBS, cyclopentylacetic acid 2 (KD = 3.4 ± 0.4 mM), identified via in silico screening. X-ray crystallography showed that 2 binds in the 7,8-diaminopelargonic acid (DAPA) pocket of MtDTBS. Appending an acidic group to the para-position of the aromatic ring of the scaffold revealed compounds 4c and 4d as more potent binders, with KD = 19 ± 5 and 17 ± 1 μM, respectively. Further optimization identified tetrazole 7a as a particularly potent binder (KD = 57 ± 5 nM) and inhibitor (Ki = 5 ± 1 μM) of MtDTBS. Our findings highlight the first reported inhibitors of MtDTBS and serve as a platform for the further development of potent inhibitors and novel therapeutics for the treatment of tuberculosis.
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Affiliation(s)
- Nicholas C. Schumann
- Department of Chemistry, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- Centre for Nanoscale BioPhotonics (CNBP), University of Adelaide, Adelaide, SA 5005, Australia
- Institute of Photonics and Advanced Sensing (IPAS), School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Kwang Jun Lee
- Department of Chemistry, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- Centre for Nanoscale BioPhotonics (CNBP), University of Adelaide, Adelaide, SA 5005, Australia
- Institute of Photonics and Advanced Sensing (IPAS), School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Andrew P. Thompson
- Alzheimer’s Research UK Oxford Drug Discovery Institute, Centre for Medicines Discovery, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Wanisa Salaemae
- Biochemistry, Division of Health and Applied Sciences, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand
| | - Jordan L. Pederick
- Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Thomas Avery
- Department of Chemistry, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- Centre for Nanoscale BioPhotonics (CNBP), University of Adelaide, Adelaide, SA 5005, Australia
- Institute of Photonics and Advanced Sensing (IPAS), School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Birgit I. Gaiser
- Centre for Nanoscale BioPhotonics (CNBP), University of Adelaide, Adelaide, SA 5005, Australia
| | - James Hodgkinson-Bean
- Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Grant W. Booker
- Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Steven W. Polyak
- Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - John B. Bruning
- Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Kate L. Wegener
- Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Andrew D. Abell
- Department of Chemistry, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- Centre for Nanoscale BioPhotonics (CNBP), University of Adelaide, Adelaide, SA 5005, Australia
- Institute of Photonics and Advanced Sensing (IPAS), School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
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3
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Wei W, Lan F, Liu Y, Wu L, Hassan BH, Wang S. Characterization of the Bifunctional Enzyme BioDA Involved in Biotin Synthesis and Pathogenicity in Aspergillus flavus. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:11971-11981. [PMID: 34591470 DOI: 10.1021/acs.jafc.1c03248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Biotin is an important enzyme cofactor that plays a key role in all three domains. The classical bifunctional enzyme BioDA in eukaryotes (such as Aspergillus flavus and Arabidopsis thaliana) is involved in the antepenultimate and penultimate steps of biotin biosynthesis. In this study, we identified a A. flavus bifunctional gene bioDA which could complement both Escherichia coli ΔEcbioD and ΔEcbioA mutants. Interestingly, the separated domain of AfBioD and AfBioA could, respectively, fuse with EcBioA and EcBioD well and work together. What is more, we found that BioDA was almost localized to the mitochondria in A. flavus, as shown by N-terminal red fluorescent protein tag fusion. Noteworthy, the subcellular localization of AfBioDA is never affected by common environmental stresses (such as hyperosmotic stress or oxidative stress). The knockout strategy demonstrated that the deletion of AfbioDA gene from the chromosome impaired the biotin de novo synthesis pathway in A. flavus. Importantly, this A. flavus mutant blocked biotin production and decreased its pathogenicity to infect peanuts. Based on the structural comparison, we found that two inhibitors (amiclenomycin and gemcitabine) could be candidates for antifungal drugs. Taken together, our findings identified the bifunctional AfbioDA gene and shed light on biotin biosynthesis in A. flavus.
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Affiliation(s)
- Wenhui Wei
- School of Life Sciences, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Faxiu Lan
- School of Life Sciences, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yinghang Liu
- School of Life Sciences, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lianghuan Wu
- School of Life Sciences, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Bachar H Hassan
- Health Sciences Center, Stony Brook University, Stony Brook, New York, New York 11794, United States
| | - Shihua Wang
- School of Life Sciences, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Gibbs NM, Su S, Lopez‐Nieves S, Mann S, Alban C, Maeda HA, Masson PH. Cadaverine regulates biotin synthesis to modulate primary root growth in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1283-1298. [PMID: 34250670 PMCID: PMC8518694 DOI: 10.1111/tpj.15417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/23/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Cadaverine, a polyamine, has been linked to modification of root growth architecture and response to environmental stresses in plants. However, the molecular mechanisms that govern the regulation of root growth by cadaverine are largely unexplored. Here we conducted a forward genetic screen and isolated a mutation, cadaverine hypersensitive 3 (cdh3), which resulted in increased root-growth sensitivity to cadaverine, but not other polyamines. This mutation affects the BIO3-BIO1 biotin biosynthesis gene. Exogenous supply of biotin and a pathway intermediate downstream of BIO1, 7,8-diaminopelargonic acid, suppressed this cadaverine sensitivity phenotype. An in vitro enzyme assay showed cadaverine inhibits the BIO3-BIO1 activity. Furthermore, cadaverine-treated seedlings displayed reduced biotinylation of Biotin Carboxyl Carrier Protein 1 of the acetyl-coenzyme A carboxylase complex involved in de novo fatty acid biosynthesis, resulting in decreased accumulation of triacylglycerides. Taken together, these results revealed an unexpected role of cadaverine in the regulation of biotin biosynthesis, which leads to modulation of primary root growth of plants.
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Affiliation(s)
- Nicole M. Gibbs
- Laboratory of GeneticsUniversity of Wisconsin‐MadisonMadisonWI53706USA
- Present address:
Plant Molecular and Cellular Biology LaboratorySalk Institute for Biological StudiesLa JollaCA92037USA
| | - Shih‐Heng Su
- Laboratory of GeneticsUniversity of Wisconsin‐MadisonMadisonWI53706USA
| | | | - Stéphane Mann
- Muséum National d'Histoire NaturelleUMR 7245CNRSMNHNMolécules de Communication et Adaptation des Micro‐organismesCP 5457 Rue CuvierParis75005France
| | - Claude Alban
- Université Grenoble AlpesINRAECEACNRSIRIGLPCVGrenoble38000France
| | - Hiroshi A. Maeda
- Department of BotanyUniversity of Wisconsin‐MadisonMadisonWI53706USA
| | - Patrick H. Masson
- Laboratory of GeneticsUniversity of Wisconsin‐MadisonMadisonWI53706USA
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5
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XRE-Type Regulator BioX Acts as a Negative Transcriptional Factor of Biotin Metabolism in Riemerella anatipestifer. J Bacteriol 2021; 203:e0018121. [PMID: 33972354 DOI: 10.1128/jb.00181-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biotin is essential for the growth and pathogenicity of microorganisms. Damage to biotin biosynthesis results in impaired bacterial growth and decreased virulence in vivo. However, the mechanisms of biotin biosynthesis in Riemerella anatipestifer remain unclear. In this study, two R. anatipestifer genes associated with biotin biosynthesis were identified. AS87_RS05840 encoded a BirA protein lacking the N-terminal winged helix-turn-helix DNA binding domain, identifying it as a group I biotin protein ligase, and AS87_RS09325 encoded a BioX protein, which was in the helix-turn-helix xenobiotic response element family of transcription factors. Electrophoretic mobility shift assays demonstrated that BioX bound to the promoter region of bioF. In addition, the R. anatipestifer genes bioF (encoding 7-keto-8-aminopelargonic acid synthase), bioD (encoding dethiobiotin synthase), and bioA (encoding 7,8-diaminopelargonic acid synthase) were in an operon and were regulated by BioX. Quantitative reverse transcription-PCR showed that transcription of the bioFDA operon increased in the mutant Yb2ΔbioX in the presence of excessive biotin, compared with that in the wild-type strain Yb2, suggesting that BioX acted as a repressor of biotin biosynthesis. Streptavidin blot analysis showed that BirA caused biotinylation of BioX, indicating that biotinylated BioX was involved in metabolic pathways. Moreover, as determined by the median lethal dose, the virulence of Yb2ΔbioX was attenuated 500-fold compared with that of Yb2. To summarize, the genes birA and bioX were identified in R. anatipestifer, and BioX was found to act as a repressor of the bioFDA operon involved in the biotin biosynthesis pathway and identified as a bacterial virulence factor. IMPORTANCE Riemerella anatipestifer is a causative agent of diseases in ducks, geese, turkeys, and various other domestic and wild birds. Our study reveals that biotin synthesis of R. anatipestifer is regulated by the BioX through binding to the promoter region of the bioF gene to inhibit transcription of the bioFDA operon. Moreover, bioX is required for R. anatipestifer pathogenicity, suggesting that BioX is a potential target for treatment of the pathogen. R. anatipestifer BioX has thus been identified as a novel negative regulator involved in biotin metabolism and associated with bacterial virulence in this study.
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Bockman MR, Mishra N, Aldrich CC. The Biotin Biosynthetic Pathway in Mycobacterium tuberculosis is a Validated Target for the Development of Antibacterial Agents. Curr Med Chem 2020; 27:4194-4232. [PMID: 30663561 DOI: 10.2174/0929867326666190119161551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/14/2018] [Accepted: 01/12/2019] [Indexed: 12/11/2022]
Abstract
Mycobacterium tuberculosis, responsible for Tuberculosis (TB), remains the leading cause of mortality among infectious diseases worldwide from a single infectious agent, with an estimated 1.7 million deaths in 2016. Biotin is an essential cofactor in M. tuberculosis that is required for lipid biosynthesis and gluconeogenesis. M. tuberculosis relies on de novo biotin biosynthesis to obtain this vital cofactor since it cannot scavenge sufficient biotin from a mammalian host. The biotin biosynthetic pathway in M. tuberculosis has been well studied and rigorously genetically validated providing a solid foundation for medicinal chemistry efforts. This review examines the mechanism and structure of the enzymes involved in biotin biosynthesis and ligation, summarizes the reported genetic validation studies of the pathway, and then analyzes the most promising inhibitors and natural products obtained from structure-based drug design and phenotypic screening.
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Affiliation(s)
- Matthew R Bockman
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Neeraj Mishra
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
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7
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Singh S, Khare G, Bahal RK, Ghosh PC, Tyagi AK. Identification of Mycobacterium tuberculosis BioA inhibitors by using structure-based virtual screening. DRUG DESIGN DEVELOPMENT AND THERAPY 2018; 12:1065-1079. [PMID: 29750019 PMCID: PMC5935190 DOI: 10.2147/dddt.s144240] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Background 7,8-Diaminopelargonic acid synthase (BioA), an enzyme of biotin biosynthesis pathway, is a well-known promising target for anti-tubercular drug development. Methods In this study, structure-based virtual screening was employed against the active site of BioA to identify new chemical entities for BioA inhibition and top ranking compounds were evaluated for their ability to inhibit BioA enzymatic activity. Results Seven compounds inhibited BioA enzymatic activity by greater than 60% at 100 μg/mL with most potent compounds being A36, A35 and A65, displaying IC50 values of 10.48 μg/mL (28.94 μM), 33.36 μg/mL (88.16 μM) and 39.17 μg/mL (114.42 μM), respectively. Compounds A65 and A35 inhibited Mycobacterium tuberculosis (M. tuberculosis) growth with MIC90 of 20 μg/mL and 80 μg/mL, respectively, whereas compound A36 exhibited relatively weak inhibition of M. tuberculosis growth (83% inhibition at 200 μg/mL). Compound A65 emerged as the most potent compound identified in our study that inhibited BioA enzymatic activity and growth of the pathogen and possessed drug-like properties. Conclusion Our study has identified a few hit molecules against M. tuberculosis BioA that can act as potential candidates for further development of potent anti-tubercular therapeutic agents.
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Affiliation(s)
- Swati Singh
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - Garima Khare
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - Ritika Kar Bahal
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - Prahlad C Ghosh
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - Anil K Tyagi
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India.,Guru Gobind Singh Indraprastha University, New Delhi, India
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Taira J, Morita K, Kawashima S, Umei T, Baba H, Maruoka T, Komatsu H, Sakamoto H, Sacchettini JC, Aoki S. Identification of a novel class of small compounds with anti-tuberculosis activity by in silico structure-based drug screening. J Antibiot (Tokyo) 2017; 70:1057-1064. [PMID: 28951604 DOI: 10.1038/ja.2017.106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 06/29/2017] [Accepted: 08/07/2017] [Indexed: 01/24/2023]
Abstract
The enzymes responsible for biotin biosynthesis in mycobacteria have been considered as potential drug targets owing to the important role in infection and cell survival that the biotin synthetic pathway plays in Mycobacterium tuberculosis. Among the enzymes that comprise mycobacterium biotin biosynthesis systems, 7,8-diaminopelargonic acid synthase (DAPAS) plays an essential role during the stationary phase in bacterial growth. In this study, compounds that inhibit mycobacterial DAPAS were screened in the virtual chemical library using an in silico structure-based drug screening (SBDS) technique, and the antimycobacterial activity of the selected compounds was validated experimentally. The DOCK-GOLD programs utilized by in silico SBDS facilitated the identification of a compound, referred to as KMD6, with potent inhibitory effects on the growth of model mycobacteria (M. smegmatis). The subsequent compound search, which was based on the structural features of KMD6, resulted in identification of three additional active compounds, designated as KMDs3, KMDs9 and KMDs10. The inhibitory effect of these compounds was comparable to that of isoniazid, which is a first-line antituberculosis drug. The high antimycobacterial activity of KMD6, KMDs9 and KMDs10 was maintained on the experiment with M. tuberculosis. Of the active compounds identified, KMDs9 would be a promising pharmacophore, owing to its long-term antimycobacterial effect and lack of cytotoxicity.
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Affiliation(s)
- Junichi Taira
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
| | - Koji Morita
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
| | - Shotaro Kawashima
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
| | - Tomohiro Umei
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
| | - Hiroki Baba
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
| | - Taira Maruoka
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
| | - Hideyuki Komatsu
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
| | - Hiroshi Sakamoto
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
| | - James C Sacchettini
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas, USA
| | - Shunsuke Aoki
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan
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Maitra A, Kamil TK, Shaik M, Danquah CA, Chrzastek A, Bhakta S. Early diagnosis and effective treatment regimens are the keys to tackle antimicrobial resistance in tuberculosis (TB): A report from Euroscicon's international TB Summit 2016. Virulence 2017; 8:1005-1024. [PMID: 27813702 PMCID: PMC5626228 DOI: 10.1080/21505594.2016.1256536] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/27/2016] [Indexed: 12/22/2022] Open
Abstract
To say that tuberculosis (TB) has regained a strong foothold in the global human health and wellbeing scenario would be an understatement. Ranking alongside HIV/AIDS as the top reason for mortality due to a single infectious disease, the impact of TB extends far into socio-economic context worldwide. As global efforts led by experts and political bodies converge to mitigate the predicted outcome of growing antimicrobial resistance, the academic community of students, practitioners and researchers have mobilised to develop integrated, inter-disciplinary programmes to bring the plans of the former to fruition. Enabling this crucial requirement for unimpeded dissemination of scientific discovery was the TB Summit 2016, held in London, United Kingdom. This report critically discusses the recent breakthroughs made in diagnostics and treatment while bringing to light the major hurdles in the control of the disease as discussed in the course of the 3-day international event. Conferences and symposia such as these are the breeding grounds for successful local and global collaborations and therefore must be supported to expand the understanding and outreach of basic science research.
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Affiliation(s)
- Arundhati Maitra
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Tengku Karmila Kamil
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Monisha Shaik
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Cynthia Amaning Danquah
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Alina Chrzastek
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Sanjib Bhakta
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
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Billones JB, Carrillo MCO, Organo VG, Sy JBA, Clavio NAB, Macalino SJY, Emnacen IA, Lee AP, Ko PKL, Concepcion GP. In silico discovery and in vitro activity of inhibitors against Mycobacterium tuberculosis 7,8-diaminopelargonic acid synthase ( Mtb BioA). DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:563-574. [PMID: 28280303 PMCID: PMC5338852 DOI: 10.2147/dddt.s119930] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Computer-aided drug discovery and development approaches such as virtual screening, molecular docking, and in silico drug property calculations have been utilized in this effort to discover new lead compounds against tuberculosis. The enzyme 7,8-diaminopelargonic acid aminotransferase (BioA) in Mycobacterium tuberculosis (Mtb), primarily involved in the lipid biosynthesis pathway, was chosen as the drug target due to the fact that humans are not capable of synthesizing biotin endogenously. The computational screening of 4.5 million compounds from the Enamine REAL database has ultimately yielded 45 high-scoring, high-affinity compounds with desirable in silico absorption, distribution, metabolism, excretion, and toxicity properties. Seventeen of the 45 compounds were subjected to bioactivity validation using the resazurin microtiter assay. Among the 4 actives, compound 7 ((Z)-N-(2-isopropoxyphenyl)-2-oxo-2-((3-(trifluoromethyl)cyclohexyl)amino)acetimidic acid) displayed inhibitory activity up to 83% at 10 μg/mL concentration against the growth of the Mtb H37Ra strain.
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Affiliation(s)
- Junie B Billones
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines; Institute of Pharmaceutical Sciences, National Institutes of Health, University of the Philippines Manila, Manila, Philippines
| | - Maria Constancia O Carrillo
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines
| | - Voltaire G Organo
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines
| | - Jamie Bernadette A Sy
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines
| | - Nina Abigail B Clavio
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines
| | - Stephani Joy Y Macalino
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines
| | - Inno A Emnacen
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines
| | - Alexandra P Lee
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines
| | - Paul Kenny L Ko
- OVPAA-EIDR Program, "Computer-Aided Discovery of Compounds for the Treatment of Tuberculosis in the Philippines", Department of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines
| | - Gisela P Concepcion
- Marine Science Institute, College of Science, University of the Philippines Diliman, Quezon City, Philippines
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11
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The Role of Biotin in Bacterial Physiology and Virulence: a Novel Antibiotic Target for
Mycobacterium tuberculosis. Microbiol Spectr 2016; 4. [DOI: 10.1128/microbiolspec.vmbf-0008-2015] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
Biotin is an essential cofactor for enzymes present in key metabolic pathways such as fatty acid biosynthesis, replenishment of the tricarboxylic acid cycle, and amino acid metabolism. Biotin is synthesized
de novo
in microorganisms, plants, and fungi, but this metabolic activity is absent in mammals, making biotin biosynthesis an attractive target for antibiotic discovery. In particular, biotin biosynthesis plays important metabolic roles as the sole source of biotin in all stages of the
Mycobacterium tuberculosis
life cycle due to the lack of a transporter for scavenging exogenous biotin. Biotin is intimately associated with lipid synthesis where the products form key components of the mycobacterial cell membrane that are critical for bacterial survival and pathogenesis. In this review we discuss the central role of biotin in bacterial physiology and highlight studies that demonstrate the importance of its biosynthesis for virulence. The structural biology of the known biotin synthetic enzymes is described alongside studies using structure-guided design, phenotypic screening, and fragment-based approaches to drug discovery as routes to new antituberculosis agents.
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12
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Evans JC, Mizrahi V. The application of tetracyclineregulated gene expression systems in the validation of novel drug targets in Mycobacterium tuberculosis. Front Microbiol 2015; 6:812. [PMID: 26300875 PMCID: PMC4523840 DOI: 10.3389/fmicb.2015.00812] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 07/23/2015] [Indexed: 12/12/2022] Open
Abstract
Although efforts to identify novel therapies for the treatment of tuberculosis have led to the identification of several promising drug candidates, the identification of high-quality hits from conventional whole-cell screens remains disappointingly low. The elucidation of the genome sequence of Mycobacterium tuberculosis (Mtb) facilitated a shift to target-based approaches to drug design but these efforts have proven largely unsuccessful. More recently, regulated gene expression systems that enable dose-dependent modulation of gene expression have been applied in target validation to evaluate the requirement of individual genes for the growth of Mtb both in vitro and in vivo. Notably, these systems can also provide a measure of the extent to which putative targets must be depleted in order to manifest a growth inhibitory phenotype. Additionally, the successful implementation of Mtb strains engineered to under-express specific molecular targets in whole-cell screens has enabled the simultaneous identification of cell-permeant inhibitors with defined mechanisms of action. Here, we review the application of tetracycline-regulated gene expression systems in the validation of novel drug targets in Mtb, highlighting both the strengths and limitations associated with this approach to target validation.
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Affiliation(s)
- Joanna C. Evans
- South African Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research UnitCape Town, South Africa
- DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine and Division of Medical Microbiology, Faculty of Health Sciences, University of Cape TownCape Town, South Africa
| | - Valerie Mizrahi
- South African Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research UnitCape Town, South Africa
- DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine and Division of Medical Microbiology, Faculty of Health Sciences, University of Cape TownCape Town, South Africa
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13
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Dai R, Geders TW, Liu F, Park SW, Schnappinger D, Aldrich CC, Finzel BC. Fragment-based exploration of binding site flexibility in Mycobacterium tuberculosis BioA. J Med Chem 2015; 58:5208-17. [PMID: 26068403 DOI: 10.1021/acs.jmedchem.5b00092] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The PLP-dependent transaminase (BioA) of Mycobacterium tuberculosis and other pathogens that catalyzes the second step of biotin biosynthesis is a now well-validated target for antibacterial development. Fragment screening by differential scanning fluorimetry has been performed to discover new chemical scaffolds and promote optimization of existing inhibitors. Calorimetry confirms binding of six molecules with high ligand efficiency. Thermodynamic data identifies which molecules bind with the enthalpy driven stabilization preferred in compounds that represent attractive starting points for future optimization. Crystallographic characterization of complexes with these molecules reveals the dynamic nature of the BioA active site. Different side chain conformational states are stabilized in response to binding by different molecules. A detailed analysis of conformational diversity in available BioA structures is presented, resulting in the identification of two states that might be targeted with molecular scaffolds incorporating well-defined conformational attributes. This new structural data can be used as part of a scaffold hopping strategy to further optimize existing inhibitors or create new small molecules with improved therapeutic potential.
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Affiliation(s)
- Ran Dai
- †Department of Medicinal Chemistry, University of Minnesota, 8-101 Weaver-Densford, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
| | - Todd W Geders
- †Department of Medicinal Chemistry, University of Minnesota, 8-101 Weaver-Densford, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
| | - Feng Liu
- †Department of Medicinal Chemistry, University of Minnesota, 8-101 Weaver-Densford, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
| | - Sae Woong Park
- ‡Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, United States
| | - Dirk Schnappinger
- ‡Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, United States
| | - Courtney C Aldrich
- †Department of Medicinal Chemistry, University of Minnesota, 8-101 Weaver-Densford, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
| | - Barry C Finzel
- †Department of Medicinal Chemistry, University of Minnesota, 8-101 Weaver-Densford, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
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14
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Park SW, Casalena DE, Wilson DJ, Dai R, Nag PP, Liu F, Boyce JP, Bittker JA, Schreiber SL, Finzel BC, Schnappinger D, Aldrich CC. Target-based identification of whole-cell active inhibitors of biotin biosynthesis in Mycobacterium tuberculosis. CHEMISTRY & BIOLOGY 2015; 22:76-86. [PMID: 25556942 PMCID: PMC4305006 DOI: 10.1016/j.chembiol.2014.11.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/29/2014] [Accepted: 11/18/2014] [Indexed: 12/31/2022]
Abstract
Biotin biosynthesis is essential for survival and persistence of Mycobacterium tuberculosis (Mtb) in vivo. The aminotransferase BioA, which catalyzes the antepenultimate step in the biotin pathway, has been established as a promising target due to its vulnerability to chemical inhibition. We performed high-throughput screening (HTS) employing a fluorescence displacement assay and identified a diverse set of potent inhibitors including many diversity-oriented synthesis (DOS) scaffolds. To efficiently select only hits targeting biotin biosynthesis, we then deployed a whole-cell counterscreen in biotin-free and biotin-containing medium against wild-type Mtb and in parallel with isogenic bioA Mtb strains that possess differential levels of BioA expression. This counterscreen proved crucial to filter out compounds whose whole-cell activity was off target as well as identify hits with weak, but measurable whole-cell activity in BioA-depleted strains. Several of the most promising hits were cocrystallized with BioA to provide a framework for future structure-based drug design efforts.
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Affiliation(s)
- Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10065, USA
| | | | - Daniel J Wilson
- Center for Drug Design, University of Minnesota, Minneapolis, MN 55455, USA
| | - Ran Dai
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Partha P Nag
- The Broad Institute Probe Development Center, Cambridge, MA 02142, USA
| | - Feng Liu
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jim P Boyce
- Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-6604, USA
| | - Joshua A Bittker
- The Broad Institute Probe Development Center, Cambridge, MA 02142, USA
| | | | - Barry C Finzel
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10065, USA.
| | - Courtney C Aldrich
- Center for Drug Design, University of Minnesota, Minneapolis, MN 55455, USA; Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
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15
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Dai R, Wilson DJ, Geders TW, Aldrich CC, Finzel BC. Inhibition of Mycobacterium tuberculosis transaminase BioA by aryl hydrazines and hydrazides. Chembiochem 2014; 15:575-86. [PMID: 24482078 PMCID: PMC4020011 DOI: 10.1002/cbic.201300748] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Indexed: 01/22/2023]
Abstract
7,8-Diaminopelargonic acid synthase (BioA) of Mycobacterium tuberculosis is a recently validated target for therapeutic intervention in the treatment of tuberculosis (TB). Using biophysical fragment screening and structural characterization of compounds, we have identified a potent aryl hydrazine inhibitor of BioA that reversibly modifies the pyridoxal-5'-phosphate (PLP) cofactor, forming a stable quinonoid. Analogous hydrazides also form covalent adducts that can be observed crystallographically but are incapable of inactivating the enzyme. In the X-ray crystal structures, small molecules induce unexpected conformational remodeling in the substrate binding site. We compared these conformational changes to those induced upon binding of the substrate (7-keto-8-aminopelargonic acid), and characterized the inhibition kinetics and the X-ray crystal structures of BioA with the hydrazine compound and analogues to unveil the mechanism of this reversible covalent modification.
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Affiliation(s)
- Ran Dai
- Department of Medicinal Chemistry University of Minnesota 308 Harvard St. SE, Minneapolis, MN 55455, United States
| | - Daniel J. Wilson
- Center for Drug Design University of Minnesota Academic Health Center, U of Minnesota, MN, 55455, United States
| | - Todd W. Geders
- Department of Medicinal Chemistry University of Minnesota 308 Harvard St. SE, Minneapolis, MN 55455, United States
| | - Courtney C. Aldrich
- Department of Medicinal Chemistry University of Minnesota 308 Harvard St. SE, Minneapolis, MN 55455, United States
| | - Barry C. Finzel
- Department of Medicinal Chemistry University of Minnesota 308 Harvard St. SE, Minneapolis, MN 55455, United States
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16
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Shi C, Aldrich CC. Design and synthesis of potential mechanism-based inhibitors of the aminotransferase BioA involved in biotin biosynthesis. J Org Chem 2012; 77:6051-8. [PMID: 22724679 DOI: 10.1021/jo3008435] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BioA, a pyridoxal 5'-phosphate (PLP) dependent aminotransferase, catalyzes the second step of biotin biosynthesis, converting 7-keto-8-aminopelargonic acid (KAPA) into 7,8-diaminopelargonic acid (DAPA). Amiclenomycin (ACM) isolated from cultures of different Streptomyces strains is a potent mechanism-based inhibitor of BioA that operates via an aromatization mechanism, irreversibly labeling the PLP cofactor. However, ACM is plagued by inherent chemical stability. Herein we describe the synthesis of four inhibitors, inspired by ACM but containing an allylic amine as the chemical warhead, designed to both improve stability and operate via a complementary Michael addition-pathway upon enzymatic oxidation of the allylic amine substrate to an enimine. Acyclic analogue M-1 contains a terminal olefin as the pro-Michael acceptor. The synthesis of M-1 features an alkyne-zipper reaction and the Overman rearrangement as key synthetic operations. The cyclic analogues M-2/3/4 contain either an endocyclic or exocyclic olefin as the pro-Michael acceptor. These were all prepared using a common strategy employing DIBAL reduction of a precursor bicyclic lactam, followed by in situ Horner-Wadsworth-Emmons (HWE) olefination as the key synthetic steps.
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Affiliation(s)
- Ce Shi
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
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17
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Salaemae W, Azhar A, Booker GW, Polyak SW. Biotin biosynthesis in Mycobacterium tuberculosis: physiology, biochemistry and molecular intervention. Protein Cell 2012; 2:691-5. [PMID: 21976058 DOI: 10.1007/s13238-011-1100-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Biotin is an important micronutrient that serves as an essential enzyme cofactor. Bacteria obtain biotin either through de novo synthesis or by active uptake from exogenous sources. Mycobacteria are unusual amongst bacteria in that their primary source of biotin is through de novo synthesis. Here we review the importance of biotin biosynthesis in the lifecycle of Mycobacteria. Genetic screens designed to identify key metabolic processes have highlighted a role for the biotin biosynthesis in bacilli growth, infection and survival during the latency phase. These studies help to establish the biotin biosynthetic pathway as a potential drug target for new anti-tuberculosis agents.
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Affiliation(s)
- Wanisa Salaemae
- School of Molecular and Biomedical Sciences, University of Adelaide, South Australia 5005, Australia
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18
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Shi C, Geders TW, Park SW, Wilson DJ, Boshoff HI, Orisadipe A, Barry CE, Schnappinger D, Finzel BC, Aldrich CC. Mechanism-based inactivation by aromatization of the transaminase BioA involved in biotin biosynthesis in Mycobaterium tuberculosis. J Am Chem Soc 2011; 133:18194-201. [PMID: 21988601 PMCID: PMC3222238 DOI: 10.1021/ja204036t] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BioA catalyzes the second step of biotin biosynthesis, and this enzyme represents a potential target to develop new antitubercular agents. Herein we report the design, synthesis, and biochemical characterization of a mechanism-based inhibitor (1) featuring a 3,6-dihydropyrid-2-one heterocycle that covalently modifies the pyridoxal 5'-phosphate (PLP) cofactor of BioA through aromatization. The structure of the PLP adduct was confirmed by MS/MS and X-ray crystallography at 1.94 Å resolution. Inactivation of BioA by 1 was time- and concentration-dependent and protected by substrate. We used a conditional knock-down mutant of M. tuberculosis to demonstrate the antitubercular activity of 1 correlated with BioA expression, and these results provide support for the designed mechanism of action.
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Affiliation(s)
- Ce Shi
- Center for Drug Design, Academic Health Center, University of Minnesota, MN, 55455, United States
| | - Todd W. Geders
- Department of Medicinal Chemistry, University of Minnesota, MN, 55455, United States
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, 10065, United States
| | - Daniel J. Wilson
- Center for Drug Design, Academic Health Center, University of Minnesota, MN, 55455, United States
| | - Helena I. Boshoff
- Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, Bethesda, MD, 20892, United States
| | - Abayomi Orisadipe
- Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, Bethesda, MD, 20892, United States
| | - Clifton E. Barry
- Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, Bethesda, MD, 20892, United States
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, 10065, United States
| | - Barry C. Finzel
- Department of Medicinal Chemistry, University of Minnesota, MN, 55455, United States
| | - Courtney C. Aldrich
- Center for Drug Design, Academic Health Center, University of Minnesota, MN, 55455, United States
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19
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A continuous fluorescence displacement assay for BioA: an enzyme involved in biotin biosynthesis. Anal Biochem 2011; 416:27-38. [PMID: 21621502 DOI: 10.1016/j.ab.2011.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 04/30/2011] [Accepted: 05/02/2011] [Indexed: 11/23/2022]
Abstract
Cofactor biosynthetic pathways represent a rich source of potential antibiotic targets. The second step in biotin biosynthesis is performed by BioA, a pyridoxal 5'-phosphate (PLP)-dependent enzyme. This enzyme has been confirmed as a candidate target in Mycobacterium tuberculosis; however, the current bioassay used to measure BioA activity is cumbersome and low throughput. Here we describe the design, development, and optimization of a continuous coupled fluorescence displacement assay to measure BioA activity. In this coupled assay, BioD converts the product of the BioA-catalyzed reaction into dethiobiotin, which is subsequently detected by displacement of a fluorescently labeled dethiobiotin probe from streptavidin. The assay was further adapted to a high-throughput screening format and validated against the LOPAC(1280) library.
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20
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Mann S, Ploux O. Pyridoxal-5'-phosphate-dependent enzymes involved in biotin biosynthesis: structure, reaction mechanism and inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:1459-66. [PMID: 21182990 DOI: 10.1016/j.bbapap.2010.12.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 11/04/2010] [Accepted: 12/10/2010] [Indexed: 11/26/2022]
Abstract
The four last steps of biotin biosynthesis, starting from pimeloyl-CoA, are conserved among all the biotin-producing microorganisms. Two enzymes of this pathway, the 8-amino-7-oxononanoate synthase (AONS) and the 7,8-diaminopelargonic acid aminotransferase (DAPA AT) are dependent on pyridoxal-5'-phosphate (PLP). This review summarizes our current understanding of the structure, reaction mechanism and inhibition on these two interesting enzymes. Mechanistic studies as well as the determination of the crystal structure of AONS have revealed a complex mechanism involving an acylation with inversion of configuration and a decarboxylation with retention of configuration. This reaction mechanism is shared by the homologous 5-aminolevulinate synthase and serine palmitoyltransferase. While the reaction catalyzed by DAPA AT is a classical PLP-dependent transamination, the inactivation of this enzyme by amiclenomycin, a natural antibiotic that is active against Mycobacterium tuberculosis, involves the irreversible formation of an adduct between PLP and amiclenomycin. Mechanistic and structural studies allowed the complete description of this unique inactivation mechanism. Several potent inhibitors of these two PLP-dependent enzymes have been prepared and might be useful as starting points for the design of herbicides or antibiotics. This article is part of a Special Issue entitled: Pyridoxal Phospate Enzymology.
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Affiliation(s)
- Stéphane Mann
- Laboratoire Charles Friedel, ENSCP Chimie ParisTech, UMR CNRS 7223, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05, France
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21
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Dey S, Lane JM, Lee RE, Rubin EJ, Sacchettini JC. Structural characterization of the Mycobacterium tuberculosis biotin biosynthesis enzymes 7,8-diaminopelargonic acid synthase and dethiobiotin synthetase . Biochemistry 2010; 49:6746-60. [PMID: 20565114 DOI: 10.1021/bi902097j] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mycobacterium tuberculosis (Mtb) depends on biotin synthesis for survival during infection. In the absence of biotin, disruption of the biotin biosynthesis pathway results in cell death rather than growth arrest, an unusual phenotype for an Mtb auxotroph. Humans lack the enzymes for biotin production, making the proteins of this essential Mtb pathway promising drug targets. To this end, we have determined the crystal structures of the second and third enzymes of the Mtb biotin biosynthetic pathway, 7,8-diaminopelargonic acid synthase (DAPAS) and dethiobiotin synthetase (DTBS), at respective resolutions of 2.2 and 1.85 A. Superimposition of the DAPAS structures bound either to the SAM analogue sinefungin or to 7-keto-8-aminopelargonic acid (KAPA) allowed us to map the putative binding site for the substrates and to propose a mechanism by which the enzyme accommodates their disparate structures. Comparison of the DTBS structures bound to the substrate 7,8-diaminopelargonic acid (DAPA) or to ADP and the product dethiobiotin (DTB) permitted derivation of an enzyme mechanism. There are significant differences between the Mtb enzymes and those of other organisms; the Bacillus subtilis DAPAS, presented here at a high resolution of 2.2 A, has active site variations and the Escherichia coli and Helicobacter pylori DTBS have alterations in their overall folds. We have begun to exploit the unique characteristics of the Mtb structures to design specific inhibitors against the biotin biosynthesis pathway in Mtb.
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Affiliation(s)
- Sanghamitra Dey
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA
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22
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Noskov SY, Roux B. Control of ion selectivity in LeuT: two Na+ binding sites with two different mechanisms. J Mol Biol 2008; 377:804-18. [PMID: 18280500 PMCID: PMC4948944 DOI: 10.1016/j.jmb.2008.01.015] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 01/07/2008] [Accepted: 01/08/2008] [Indexed: 10/22/2022]
Abstract
The x-ray structure of LeuT, a bacterial homologue of Na(+)/Cl(-)-dependent neurotransmitter transporters, provides a great opportunity to better understand the molecular basis of monovalent cation selectivity in ion-coupled transporters. LeuT possesses two ion binding sites, NA1 and NA2, which are highly selective for Na(+). Extensive all-atom free-energy molecular dynamics simulations of LeuT embedded in an explicit membrane are performed at different temperatures and various occupancy states of the binding sites to dissect the molecular mechanism of ion selectivity. The results show that the two binding sites display robust selectivity for Na(+) over K(+) or Li(+), the competing ions of most similar radii. Of particular interest, the mechanism primarily responsible for selectivity for each of the two binding sites appears to be different. In NA1, selectivity for Na(+) over K(+) arises predominantly from the strong electrostatic field arising from the negatively charged carboxylate group of the leucine substrate coordinating the ion directly. In NA2, which comprises only neutral ligands, selectivity for Na(+) is enforced by the local structural restraints arising from the hydrogen-bonding network and the covalent connectivity of the polypeptide chain surrounding the ion according to a "snug-fit" mechanism.
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Affiliation(s)
- Sergei Y Noskov
- Institute for Biocomplexity and Informatics, Department for Biological Sciences, University of Calgary, 2500 University Drive, Calgary, AB, Canada.
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23
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Scott DE, Ciulli A, Abell C. Coenzyme biosynthesis: enzyme mechanism, structure and inhibition. Nat Prod Rep 2007; 24:1009-26. [PMID: 17898895 DOI: 10.1039/b703108b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review highlights five key reactions in vitamin biosynthesis and in particular focuses on their mechanisms and inhibition and insights from structural studies. Each of the enzymes has the potential to be a target for novel antimicrobial agents.
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Affiliation(s)
- Duncan E Scott
- University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW, UK
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24
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Mann S, Ploux O. 7,8-Diaminoperlargonic acid aminotransferase from Mycobacterium tuberculosis, a potential therapeutic target. Characterization and inhibition studies. FEBS J 2006; 273:4778-89. [PMID: 16984394 DOI: 10.1111/j.1742-4658.2006.05479.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Diaminopelargonic acid aminotransferase (DAPA AT), which is involved in biotin biosynthesis, catalyzes the transamination of 8-amino-7-oxononanoic acid (KAPA) using S-adenosyl-l-methionine (AdoMet) as amino donor. Mycobacterium tuberculosis DAPA AT, a potential therapeutic target, has been overproduced in Escherichia coli and purified to homogeneity using a single efficient step on a nickel-affinity column. The enzyme shows an electronic absorption spectrum typical of pyridoxal 5'-phosphate-dependent enzymes and behaves as a homotetramer in solution. The pH profile of the activity at saturation shows a single ionization group with a pK(a) of 8.0, which was attributed to the active-site lysine residue. The enzyme shows a Ping Pong Bi Bi kinetic mechanism with strong substrate inhibition with the following parameters: K(mAdoMet) = 0.78 +/- 0.20 mm, K(mKAPA) = 3.8 +/- 1.0 microm, k(cat) = 1.0 +/- 0.2 min(-1), K(iKAPA) = 14 +/- 2 microm. Amiclenomycin and a new analogue, 4-(4c-aminocyclohexa-2,5-dien-1r-yl)propanol (referred to as compound 1), were shown to be suicide substrates of this enzyme, with the following inactivation parameters: K(i) = 12 +/- 2 microm, k(inact) = 0.35 +/- 0.05 min(-1), and K(i) = 20 +/- 2 microm, k(inact) = 0.56 +/- 0.05 min(-1), for amiclenomycin and compound 1, respectively. The inactivation was irreversible, and the partition ratios were 1.0 and 1.1 for amiclenomycin and compound 1, respectively, which make these inactivators particularly efficient. compound 1 (100 microg.mL(-1)) completely inhibited the growth of an E. coli C268bioA mutant strain transformed with a plasmid expressing the M. tuberculosis bioA gene, coding for DAPA AT. Reversal of the antibiotic effect was observed on the addition of biotin or DAPA. Thus, compound 1 specifically targets DAPA AT in vivo.
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Affiliation(s)
- Stéphane Mann
- Synthèse Structure et Fonction de Molécules Bioactives, Université Pierre et Marie Curie-Paris 6, UMR 7613, Paris, France
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25
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Mann S, Marquet A, Ploux O. Inhibition of 7,8-diaminopelargonic acid aminotransferase by amiclenomycin and analogues. Biochem Soc Trans 2005; 33:802-5. [PMID: 16042602 DOI: 10.1042/bst0330802] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cis and trans stereoisomers of amiclenomycin, a natural L-amino acid antibiotic, have been prepared using unequivocal routes. By using 1H NMR spectroscopy, the configuration of the six-membered ring of natural amiclenomycin was shown to be cis and not trans as originally proposed. Amiclenomycin and some synthetic analogues with the cis configuration irreversibly inactivate DAPA AT (7,8-diaminopelargonic acid aminotransferase), an enzyme involved in biotin biosynthesis, by forming an aromatic PLP (pyridoxal-5'-phosphate)-inhibitor adduct that is tightly bound to the active site. The following kinetic parameters for the inactivation of Escherichia coli DAPA AT by amiclenomycin were derived: K(I)=2 microM and k(inact)=0.4 min(-1). The structure of the aromatic adduct formed upon inactivation was confirmed by UV-visible spectroscopy, X-ray crystal structure determination and MS. Because Mycobacterium tuberculosis DAPA AT is a potential drug target, this enzyme was cloned, overexpressed and purified to homogeneity for biochemical characterization.
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Affiliation(s)
- S Mann
- Synthèse, Structure et Fonction de Molécules Bioactives, UMR CNRS 7613, Université Pierre et Marie Curie, boîte 182, 4, place Jussieu, 75252 Paris Cedex 05, France.
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26
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Sandmark J, Eliot AC, Famm K, Schneider G, Kirsch JF. Conserved and Nonconserved Residues in the Substrate Binding Site of 7,8-Diaminopelargonic Acid Synthase from Escherichia coli Are Essential for Catalysis. Biochemistry 2004; 43:1213-22. [PMID: 14756557 DOI: 10.1021/bi0358059] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The vitamin B(6)-dependent enzyme 7,8-diaminopelargonic acid (DAPA) synthase catalyzes the antepenultimate step in the synthesis of biotin, the transfer of the alpha-amino group of S-adenosyl-l-methionine (SAM) to 7-keto-8-aminopelargonic acid (KAPA) to form DAPA. The Y17F, Y144F, and D147N mutations in the active site were constructed independently. The k(max)/K(m)(app) values for the half-reaction with DAPA of the Y17F and Y144F mutants are reduced by 1300- and 2900-fold, respectively, compared to the WT enzyme. Crystallographic analyses of these mutants do not show significant changes in the structure of the active site. The kinetic deficiencies, together with a structural model of the enzyme-PLP/DAPA Michaelis complex, point to a role of these two residues in recognition of the DAPA/KAPA substrates and in catalysis. The k(max)/K(m)(app) values for the half-reaction with SAM are similar to that of the WT enzyme, showing that the two tyrosine residues are not involved in this half-reaction. Mutations of the conserved Arg253 uniquely affect the SAM kinetics, thus establishing this position as part of the SAM binding site. The D147N mutant is catalytically inactive in both half-reactions. The structure of this mutant exhibits significant changes in the active site, indicating that this residue plays an important structural role. Of the four residues examined, only Tyr144 and Arg253 are strictly conserved in the available amino acid sequences of DAPA synthases. This enzyme thus provides an illustrative example that active site residues essential for catalysis are not necessarily conserved, i.e., that during evolution alternative solutions for efficient catalysis by the same enzyme arose. Decarboxylated SAM [S-adenosyl-(5')-3-methylthiopropylamine] reacts nearly as well as SAM and cannot be eliminated as a putative in vivo amino donor.
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Affiliation(s)
- Jenny Sandmark
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden
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