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Johnson S, Li H, Valentino H, Sobrado P. Mechanism of Nitrone Formation by a Flavin-Dependent Monooxygenase. Biochemistry 2024; 63:1445-1459. [PMID: 38779817 PMCID: PMC11154958 DOI: 10.1021/acs.biochem.3c00656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/07/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024]
Abstract
OxaD is a flavin-dependent monooxygenase (FMO) responsible for catalyzing the oxidation of an indole nitrogen atom, resulting in the formation of a nitrone. Nitrones serve as versatile intermediates in complex syntheses, including challenging reactions like cycloadditions. Traditional organic synthesis methods often yield limited results and involve environmentally harmful chemicals. Therefore, the enzymatic synthesis of nitrone-containing compounds holds promise for more sustainable industrial processes. In this study, we explored the catalytic mechanism of OxaD using a combination of steady-state and rapid-reaction kinetics, site-directed mutagenesis, spectroscopy, and structural modeling. Our investigations showed that OxaD catalyzes two oxidations of the indole nitrogen of roquefortine C, ultimately yielding roquefortine L. The reductive-half reaction analysis indicated that OxaD rapidly undergoes reduction and follows a "cautious" flavin reduction mechanism by requiring substrate binding before reduction can take place. This characteristic places OxaD in class A of the FMO family, a classification supported by a structural model featuring a single Rossmann nucleotide binding domain and a glutathione reductase fold. Furthermore, our spectroscopic analysis unveiled both enzyme-substrate and enzyme-intermediate complexes. Our analysis of the oxidative-half reaction suggests that the flavin dehydration step is the slow step in the catalytic cycle. Finally, through mutagenesis of the conserved D63 residue, we demonstrated its role in flavin motion and product oxygenation. Based on our findings, we propose a catalytic mechanism for OxaD and provide insights into the active site architecture within class A FMOs.
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Affiliation(s)
- Sydney
B. Johnson
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Hao Li
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Hannah Valentino
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Pablo Sobrado
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
- Center
of Drug Discovery, Virginia Tech, Blacksburg, Virginia 24061, United
States
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2
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Tilocca B, Greco V, Piras C, Ceniti C, Paonessa M, Musella V, Bava R, Palma E, Morittu VM, Spina AA, Castagna F, Urbani A, Britti D, Roncada P. The Bee Gut Microbiota: Bridging Infective Agents Potential in the One Health Context. Int J Mol Sci 2024; 25:3739. [PMID: 38612550 PMCID: PMC11012054 DOI: 10.3390/ijms25073739] [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: 02/29/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024] Open
Abstract
The bee gut microbiota plays an important role in the services the bees pay to the environment, humans and animals. Alongside, gut-associated microorganisms are vehiculated between apparently remote habitats, promoting microbial heterogeneity of the visited microcosms and the transfer of the microbial genetic elements. To date, no metaproteomics studies dealing with the functional bee microbiota are available. Here, we employ a metaproteomics approach to explore a fraction of the bacterial, fungal, and unicellular parasites inhabiting the bee gut. The bacterial community portrays a dynamic composition, accounting for specimens of human and animal concern. Their functional features highlight the vehiculation of virulence and antimicrobial resistance traits. The fungal and unicellular parasite fractions include environment- and animal-related specimens, whose metabolic activities support the spatial spreading of functional features. Host proteome depicts the major bee physiological activities, supporting the metaproteomics strategy for the simultaneous study of multiple microbial specimens and their host-crosstalks. Altogether, the present study provides a better definition of the structure and function of the bee gut microbiota, highlighting its impact in a variety of strategies aimed at improving/overcoming several current hot topic issues such as antimicrobial resistance, environmental pollution and the promotion of environmental health.
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Affiliation(s)
- Bruno Tilocca
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Viviana Greco
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Catholic University of the Sacred Hearth, 00168 Rome, Italy; (V.G.); (A.U.)
- Unity of Chemistry, Biochemistry and Clinical Molecular Biology, Department of Diagnostic and Laboratory Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Cristian Piras
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Carlotta Ceniti
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Mariachiara Paonessa
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Vincenzo Musella
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Roberto Bava
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Ernesto Palma
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Valeria Maria Morittu
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Anna Antonella Spina
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Fabio Castagna
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Andrea Urbani
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Catholic University of the Sacred Hearth, 00168 Rome, Italy; (V.G.); (A.U.)
- Unity of Chemistry, Biochemistry and Clinical Molecular Biology, Department of Diagnostic and Laboratory Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Domenico Britti
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
| | - Paola Roncada
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (C.C.); (M.P.); (V.M.); (R.B.); (E.P.); (V.M.M.); (A.A.S.); (F.C.); (D.B.)
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Nie Q, Sun D, Zhu M, Tu S, Chen N, Chen H, Zhou Y, Yao G, Zhang X, Zhang T, Yang C, Tao L. Phenotypic drug susceptibility characterization and clinical outcomes of tuberculosis strains with A-probe mutation by GeneXpert MTB/RIF. BMC Infect Dis 2023; 23:832. [PMID: 38012619 PMCID: PMC10680243 DOI: 10.1186/s12879-023-08509-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 08/03/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND GeneXpert MTB/RIF (Xpert) assay was applied widely to detect Mycobacterium tuberculosis (MTB) and rifampicin resistance. METHODS Retrospectively investigated the association among treatment histories, phenotypic drug susceptibility testing (pDST) results, and clinical outcomes of patients infected with probe A absent mutation isolate confirmed by Xpert. RESULTS 63 patients with only probe A absent mutation and 40 with additional pDST results were analyzed. 24 (60.0%) patients had molecular-phenotypic discordant rifampicin (RIF) susceptibility testing results, including 12 (12/13, 92.3%) new tuberculosis (TB) patients and 12 (12/27, 44.4%) retreated ones. 28 (28/39, 71.8%) retreated patients received first-line treatment regime within two years with failed outcomes. New patients had better treatment outcomes than retreated ones (successful: 83.3% VS. 53.8%; P value = 0.02). The clinical results of RIF-susceptible TB confirmed by pDST were not better than RIF-resistant TB (successful: 62.5% VS. 50.0%; P value = 0.43). INH-resistant TB and INH-susceptible TB had similar treatment outcomes too (successful: 61.5% VS. 50.0%; P value = 0.48). 11 (11/12, 91.7%) new patients treated with the short treatment regimen (STR) had successful outcomes. CONCLUSIONS More than half of mono probe A absent isolates had RIF molecular-phenotypic discordance results, especially in new patients. Probe A mutations were significantly associated with unsuccessful clinical outcomes, whether the pDST results were RIF susceptible or not. STR was the best choice for new patients. TRIAL REGISTRATION retrospectively registered in Wuhan Jinyintan Hospital (No. 2021-KY-16).
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Affiliation(s)
- Qi Nie
- College of Life Sciences and Health, Wuhan University of Science and Technology, Hubei, China
- Department of MDR/RR-TB, Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, University of Science and Technology, Hubei Clinical Research Center for Infectious Diseases, Chinese Academy of Medical Sciences, Hubei, China
| | - Dan Sun
- Department of Interventional therapy, Wuhan Pulmonary Hospital, Hubei, China
| | - Muxin Zhu
- Department of MDR/RR-TB, Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, University of Science and Technology, Hubei Clinical Research Center for Infectious Diseases, Chinese Academy of Medical Sciences, Hubei, China
| | - Shengjin Tu
- Department of MDR/RR-TB, Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, University of Science and Technology, Hubei Clinical Research Center for Infectious Diseases, Chinese Academy of Medical Sciences, Hubei, China
| | - Nanshan Chen
- Department of MDR/RR-TB, Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, University of Science and Technology, Hubei Clinical Research Center for Infectious Diseases, Chinese Academy of Medical Sciences, Hubei, China
| | - Hua Chen
- Department of MDR/RR-TB, Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, University of Science and Technology, Hubei Clinical Research Center for Infectious Diseases, Chinese Academy of Medical Sciences, Hubei, China
| | - Yong Zhou
- Department of MDR/RR-TB, Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, University of Science and Technology, Hubei Clinical Research Center for Infectious Diseases, Chinese Academy of Medical Sciences, Hubei, China
| | - Ge Yao
- Department of MDR/RR-TB, Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, University of Science and Technology, Hubei Clinical Research Center for Infectious Diseases, Chinese Academy of Medical Sciences, Hubei, China
| | - Xiaoqing Zhang
- Department of MDR/RR-TB, Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, University of Science and Technology, Hubei Clinical Research Center for Infectious Diseases, Chinese Academy of Medical Sciences, Hubei, China
| | - Tongcun Zhang
- College of Life Sciences and Health, Wuhan University of Science and Technology, Hubei, China.
| | - Chengfeng Yang
- Hubei Provincial Center for Disease Control and Prevention, Hubei, China.
| | - Lixuan Tao
- Emergency Department, Puren Hospital, Wuhan University of science and technology, Hubei, China.
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Minerdi D, Loqui D, Sabbatini P. Monooxygenases and Antibiotic Resistance: A Focus on Carbapenems. BIOLOGY 2023; 12:1316. [PMID: 37887026 PMCID: PMC10604202 DOI: 10.3390/biology12101316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/08/2023] [Accepted: 09/15/2023] [Indexed: 10/28/2023]
Abstract
Carbapenems are a group of broad-spectrum beta-lactam antibiotics that in many cases are the last effective defense against infections caused by multidrug-resistant bacteria, such as some strains of Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Resistance to carbapenems has emerged and is beginning to spread, becoming an ongoing public-health problem of global dimensions, causing serious outbreaks, and dramatically limiting treatment options. This paper reviews the role of flavin monooxygenases in antibiotic resistance, with a specific focus on carbapenem resistance and the recently discovered mechanism mediated by Baeyer-Villiger monooxygenases. Flavin monooxygenases are enzymes involved in the metabolism and detoxification of compounds, including antibiotics. Understanding their role in antibiotic resistance is crucial. Carbapenems are powerful antibiotics used to treat severe infections caused by multidrug-resistant bacteria. However, the rise of carbapenem-resistant strains poses a significant challenge. This paper explores the mechanisms by which flavin monooxygenases confer resistance to carbapenems, examining molecular pathways and genetic factors. Additionally, this paper highlights the discovery of Baeyer-Villiger monooxygenases' involvement in antibiotic resistance. These enzymes catalyze the insertion of oxygen atoms into specific chemical bonds. Recent studies have revealed their unexpected role in promoting carbapenem resistance. Through a comprehensive analysis of the literature, this paper contributes to the understanding of the interplay between flavin monooxygenases, carbapenem resistance, and Baeyer-Villiger monooxygenases. By exploring these mechanisms, it aims to inform the development of strategies to combat antibiotic resistance, a critical global health concern.
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Affiliation(s)
- Daniela Minerdi
- Department of Agricultural, Forestry and Food Sciences, University of Turin, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy;
| | - Davide Loqui
- Emergency Department, Città della Salute e della Scienza of Turin, 10100 Turin, TO, Italy;
| | - Paolo Sabbatini
- Department of Agricultural, Forestry and Food Sciences, University of Turin, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy;
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5
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Li F, Lv Z, Zhong Z, Mao L, Chua LS, Xu L, Huang R. The Effect of Cyclosporin A on Aspergillus niger and the Possible Mechanisms Involved. Foods 2023; 12:foods12030567. [PMID: 36766095 PMCID: PMC9913951 DOI: 10.3390/foods12030567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 02/01/2023] Open
Abstract
Aspergillus niger is one of the major pathogenic fungi causing postharvest grape decay. The development of antifungal agents is beneficial to reduce the loss of grapes during storage. The aim of this study was to investigate the antifungal mechanism of cyclosporin A (CsA). It was indicated that the rot development on grapes caused by A. niger was almost completely inhibited with CsA in vivo at a concentration of 200 mg/L. The transcriptomic analysis revealed that the expression levels of genes involved in rRNA processing and ribosome biogenesis were down-regulated, whereas those related to β-glucosidases and chitinases were up-regulated. The results implied that CsA may disturb rRNA and ribosome formation to obstruct protein synthesis, accelerate chitin and glucan degradation to destruct cell walls, and ultimately reduce postharvest decay caused by A. niger in grapes. This study evaluated the potential of CsA as a grape preservative and provided new insights into the mechanisms underlying the molecular response in A. niger with the treatment of CsA.
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Affiliation(s)
- Fengming Li
- School of Life Sciences, Huizhou University, Huizhou 516001, China
- College of Food Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Zhencheng Lv
- School of Life Sciences, Huizhou University, Huizhou 516001, China
| | - Zhijuan Zhong
- School of Life Sciences, Huizhou University, Huizhou 516001, China
| | - Lutian Mao
- School of Life Sciences, Huizhou University, Huizhou 516001, China
| | - Lee Suan Chua
- Department of Bioprocess and Polymer Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysis, UTM Skudai, Johor Bahru 81310, Malaysia
| | - Liangxiong Xu
- School of Life Sciences, Huizhou University, Huizhou 516001, China
- Correspondence: (L.X.); (R.H.)
| | - Riming Huang
- College of Food Sciences, South China Agricultural University, Guangzhou 510642, China
- Correspondence: (L.X.); (R.H.)
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6
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Activation of the SigE-SigB signaling pathway by inhibition of the respiratory electron transport chain and its effect on rifampicin resistance in Mycobacterium smegmatis. J Microbiol 2022; 60:935-947. [DOI: 10.1007/s12275-022-2202-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 10/16/2022]
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7
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Surette MD, Spanogiannopoulos P, Wright GD. The Enzymes of the Rifamycin Antibiotic Resistome. Acc Chem Res 2021; 54:2065-2075. [PMID: 33877820 DOI: 10.1021/acs.accounts.1c00048] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Rifamycin antibiotics include the WHO essential medicines rifampin, rifabutin, and rifapentine. These are semisynthetic derivatives of the natural product rifamycins, originally isolated from the soil bacterium Amycolatopsis rifamycinica. These antibiotics are primarily used to treat mycobacterial infections, including tuberculosis. Rifamycins act by binding to the β-subunit of bacterial RNA polymerase, inhibiting transcription, which results in cell death. These antibiotics consist of a naphthalene core spanned by a polyketide ansa bridge. This structure presents a unique 3D configuration that engages RNA polymerase through a series of hydrogen bonds between hydroxyl groups linked to the naphthalene core and C21 and C23 of the ansa bridge. This binding occurs not in the enzyme active site where template-directed RNA synthesis occurs but instead in the RNA exit tunnel, thereby blocking productive formation of full-length RNA. In their clinical use to treat tuberculosis, resistance to rifamycin antibiotics arises principally from point mutations in RNA polymerase that decrease the antibiotic's affinity for the binding site in the RNA exit tunnel. In contrast, the rifamycin resistome of environmental mycobacteria and actinomycetes is much richer and diverse. In these organisms, rifamycin resistance includes many different enzymatic mechanisms that modify and alter the antibiotic directly, thereby inactivating it. These enzymes include ADP ribosyltransferases, glycosyltransferases, phosphotransferases, and monooxygenases.ADP ribosyltransferases catalyze group transfer of ADP ribose from the cofactor NAD+, which is more commonly deployed for metabolic redox reactions. ADP ribose is transferred to the hydroxyl linked to C23 of the antibiotic, thereby sterically blocking productive interaction with RNA polymerase. Like ADP ribosyltransferases, rifamycin glycosyl transferases also modify the hydroxyl of position C23 of rifamycins, transferring a glucose moiety from the donor molecule UDP-glucose. Unlike other antibiotic resistance kinases that transfer the γ-phosphate of ATP to inactivate antibiotics such as aminoglycosides or macrolides, rifamycin phosphotransferases are ATP-dependent dikinases. These enzymes transfer the β-phosphate of ATP to the C21 hydroxyl of the rifamycin ansa bridge. The result is modification of a critical RNA polymerase binding group that blocks productive complex formation. On the other hand, rifamycin monooxygenases are FAD-dependent enzymes that hydroxylate the naphthoquinone core. The result of this modification is untethering of the ansa chain from the naphthyl moiety, disrupting the essential 3D shape necessary for productive RNA polymerase binding and inhibition that leads to cell death.All of these enzymes have homologues in bacterial metabolism that either are their direct precursors or share common ancestors to the resistance enzyme. The diversity of these resistance mechanisms, often redundant in individual bacterial isolates, speaks to the importance of protecting RNA polymerase from these compounds and validates this enzyme as a critical antibiotic target.
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Affiliation(s)
- Matthew D. Surette
- M.G. DeGroote Institute for Infectious Disease Research, David Braley Center for Antibiotic Discovery, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 3Z5, Canada
| | - Peter Spanogiannopoulos
- M.G. DeGroote Institute for Infectious Disease Research, David Braley Center for Antibiotic Discovery, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 3Z5, Canada
| | - Gerard D. Wright
- M.G. DeGroote Institute for Infectious Disease Research, David Braley Center for Antibiotic Discovery, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 3Z5, Canada
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8
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Valentino H, Campbell AC, Schuermann JP, Sultana N, Nam HG, LeBlanc S, Tanner JJ, Sobrado P. Structure and function of a flavin-dependent S-monooxygenase from garlic ( Allium sativum). J Biol Chem 2020; 295:11042-11055. [PMID: 32527723 DOI: 10.1074/jbc.ra120.014484] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/07/2020] [Indexed: 12/26/2022] Open
Abstract
Allicin is a component of the characteristic smell and flavor of garlic (Allium sativum). A flavin-containing monooxygenase (FMO) produced by A. sativum (AsFMO) was previously proposed to oxidize S-allyl-l-cysteine (SAC) to alliin, an allicin precursor. Here, we present a kinetic and structural characterization of AsFMO that suggests a possible contradiction to this proposal. Results of steady-state kinetic analyses revealed that AsFMO exhibited negligible activity with SAC; however, the enzyme was highly active with l-cysteine, N-acetyl-l-cysteine, and allyl mercaptan. We found that allyl mercaptan with NADPH was the preferred substrate-cofactor combination. Rapid-reaction kinetic analyses showed that NADPH binds tightly (KD of ∼2 μm) to AsFMO and that the hydride transfer occurs with pro-R stereospecificity. We detected the formation of a long-wavelength band when AsFMO was reduced by NADPH, probably representing the formation of a charge-transfer complex. In the absence of substrate, the reduced enzyme, in complex with NADP+, reacted with oxygen and formed an intermediate with a spectrum characteristic of C4a-hydroperoxyflavin, which decays several orders of magnitude more slowly than the k cat The presence of substrate enhanced C4a-hydroperoxyflavin formation and, upon hydroxylation, oxidation occurred with a rate constant similar to the k cat The structure of AsFMO complexed with FAD at 2.08-Å resolution features two domains for binding of FAD and NADPH, representative of class B flavin monooxygenases. These biochemical and structural results are consistent with AsFMO being an S-monooxygenase involved in allicin biosynthesis through direct formation of sulfenic acid and not SAC oxidation.
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Affiliation(s)
- Hannah Valentino
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, USA.,Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, USA
| | - Ashley C Campbell
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Jonathan P Schuermann
- Northeastern Collaborative Access Team, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | - Nazneen Sultana
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, USA
| | - Han G Nam
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, USA
| | - Sophie LeBlanc
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, USA
| | - John J Tanner
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA .,Department of Chemistry, University of Missouri, Columbia, Missouri, USA
| | - Pablo Sobrado
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, USA .,Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, USA
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9
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Das B, Verma J, Kumar P, Ghosh A, Ramamurthy T. Antibiotic resistance in Vibrio cholerae: Understanding the ecology of resistance genes and mechanisms. Vaccine 2020; 38 Suppl 1:A83-A92. [DOI: 10.1016/j.vaccine.2019.06.031] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 04/11/2019] [Accepted: 06/04/2019] [Indexed: 11/29/2022]
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10
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Antibiotic resistance genes in the Actinobacteria phylum. Eur J Clin Microbiol Infect Dis 2019; 38:1599-1624. [PMID: 31250336 DOI: 10.1007/s10096-019-03580-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/01/2019] [Indexed: 02/07/2023]
Abstract
The Actinobacteria phylum is one of the oldest bacterial phyla that have a significant role in medicine and biotechnology. There are a lot of genera in this phylum that are causing various types of infections in humans, animals, and plants. As well as antimicrobial agents that are used in medicine for infections treatment or prevention of infections, they have been discovered of various genera in this phylum. To date, resistance to antibiotics is rising in different regions of the world and this is a global health threat. The main purpose of this review is the molecular evolution of antibiotic resistance in the Actinobacteria phylum.
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11
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Markley JL, Wencewicz TA. Tetracycline-Inactivating Enzymes. Front Microbiol 2018; 9:1058. [PMID: 29899733 PMCID: PMC5988894 DOI: 10.3389/fmicb.2018.01058] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/04/2018] [Indexed: 12/25/2022] Open
Abstract
Tetracyclines have been foundational antibacterial agents for more than 70 years. Renewed interest in tetracycline antibiotics is being driven by advancements in tetracycline synthesis and strategic scaffold modifications designed to overcome established clinical resistance mechanisms including efflux and ribosome protection. Emerging new resistance mechanisms, including enzymatic antibiotic inactivation, threaten recent progress on bringing these next-generation tetracyclines to the clinic. Here we review the current state of knowledge on the structure, mechanism, and inhibition of tetracycline-inactivating enzymes.
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Affiliation(s)
- Jana L Markley
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, United States
| | - Timothy A Wencewicz
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, United States
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Liu LK, Dai Y, Abdelwahab H, Sobrado P, Tanner JJ. Structural Evidence for Rifampicin Monooxygenase Inactivating Rifampicin by Cleaving Its Ansa-Bridge. Biochemistry 2018; 57:2065-2068. [PMID: 29578336 DOI: 10.1021/acs.biochem.8b00190] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Rifampicin monooxygenase (RIFMO) decreases the potency of rifampicin (RIF) by converting it to oxidative products. Further decomposition of RIF has been observed in bacteria producing RIFMO and contributes to RIFMO-mediated drug resistance. Here we report the first crystal structure of RIFMO in complex with the hydroxylated RIF product. The 2.10 Å resolution structure reveals a breach of the ansa aliphatic chain of RIF between naphthoquinone C2 and amide N1. Our data suggest that RIFMO catalyzes the hydroxylation of RIF at the C2 atom followed by cleavage of the ansa linkage, which leads to inactivation of the antibiotic by preventing key contacts with the RNA polymerase target.
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Affiliation(s)
| | - Yumin Dai
- Department of Biochemistry , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Heba Abdelwahab
- Department of Biochemistry , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Pablo Sobrado
- Department of Biochemistry , Virginia Tech , Blacksburg , Virginia 24061 , United States
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Koteva K, Cox G, Kelso JK, Surette MD, Zubyk HL, Ejim L, Stogios P, Savchenko A, Sørensen D, Wright GD. Rox, a Rifamycin Resistance Enzyme with an Unprecedented Mechanism of Action. Cell Chem Biol 2018; 25:403-412.e5. [PMID: 29398560 DOI: 10.1016/j.chembiol.2018.01.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 10/07/2017] [Accepted: 01/08/2018] [Indexed: 12/11/2022]
Abstract
Rifamycin monooxygenases (Rox) are present in a variety of environmental bacteria and are associated with decomposition of the clinically utilized antibiotic rifampin. Here we report the structure and function of a drug-inducible rox gene from Streptomyces venezuelae, which encodes a class A flavoprotein monooxygenase that inactivates a broad range of rifamycin antibiotics. Our findings describe a mechanism of rifamycin inactivation initiated by monooxygenation of the 2-position of the naphthyl group, which subsequently results in ring opening and linearization of the antibiotic. The result is an antibiotic that no longer adopts the basket-like structure essential for binding to the RNA exit tunnel of the target RpoB, thereby providing the molecular logic of resistance. This unique mechanism of enzymatic inactivation underpins the broad spectrum of rifamycin resistance mediated by Rox enzymes and presents a new antibiotic resistance mechanism not yet seen in microbial antibiotic detoxification.
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Affiliation(s)
- Kalinka Koteva
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Georgina Cox
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Jayne K Kelso
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Matthew D Surette
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Haley L Zubyk
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Linda Ejim
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Peter Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5G 1L6, Canada; Center for Structural Genomics of Infectious Diseases (CSGID), University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Alexei Savchenko
- Center for Structural Genomics of Infectious Diseases (CSGID), University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Dan Sørensen
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4M1, Canada
| | - Gerard D Wright
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
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Bufkin K, Sobrado P. Characterization of the Ornithine Hydroxylation Step in Albachelin Biosynthesis. Molecules 2017; 22:E1652. [PMID: 28974024 PMCID: PMC6151521 DOI: 10.3390/molecules22101652] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 09/27/2017] [Accepted: 09/28/2017] [Indexed: 11/16/2022] Open
Abstract
N-Hydroxylating monooxygenases (NMOs) are involved in siderophore biosynthesis. Siderophores are high affinity iron chelators composed of catechol and hydroxamate functional groups that are synthesized and secreted by microorganisms and plants. Recently, a new siderophore named albachelin was isolated from a culture of Amycolatopsis alba growing under iron-limiting conditions. This work focuses on the expression, purification, and characterization of the NMO, abachelin monooxygenase (AMO) from A. alba. This enzyme was purified and characterized in its holo (FAD-bound) and apo (FAD-free) forms. The apo-AMO could be reconstituted by addition of free FAD. The two forms of AMO hydroxylate ornithine, while lysine increases oxidase activity but is not hydroxylated and display low affinity for NADPH.
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Affiliation(s)
- Kendra Bufkin
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Pablo Sobrado
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
- Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061, USA.
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Abstract
Antibiotic natural products are ancient and so is resistance. Consequently, environmental bacteria harbor numerous and varied antibiotic resistance elements. Nevertheless, despite long histories of antibiotic production and exposure, environmental bacteria are not resistant to all known antibiotics. This means that there are barriers to the acquisition of a complete resistance armamentarium. The sources, distribution, and movement of resistance mechanisms in different microbes and bacterial populations are mosaic features that act as barriers to slow this movement, thus moderating the emergence of bacterial pan-resistance. This is highly relevant to understanding the emergence of resistance in pathogenic bacteria that can inform better antibiotic management practices and influence new drug discovery.
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Affiliation(s)
- Nicholas Waglechner
- Michael G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, ON, L8N 4K1, Canada
| | - Gerard D Wright
- Michael G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, ON, L8N 4K1, Canada.
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16
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Rifabutin Is Active against Mycobacterium abscessus Complex. Antimicrob Agents Chemother 2017; 61:AAC.00155-17. [PMID: 28396540 PMCID: PMC5444174 DOI: 10.1128/aac.00155-17] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/31/2017] [Indexed: 12/30/2022] Open
Abstract
Lung infections caused by Mycobacterium abscessus are emerging as a global threat to individuals with cystic fibrosis and to other patient groups. Recent evidence for human-to-human transmission worsens the situation. M. abscessus is an intrinsically multidrug-resistant pathogen showing resistance to even standard antituberculosis drugs, such as rifampin. Here, our objective was to identify existing drugs that may be employed for the treatment of M. abscessus lung disease. A collection of more than 2,700 approved drugs was screened at a single-point concentration against an M. abscessus clinical isolate. Hits were confirmed with fresh solids in dose-response experiments. For the most attractive hit, growth inhibition and bactericidal activities against reference strains of the three M. abscessus subspecies and a collection of clinical isolates were determined. Surprisingly, the rifampin derivative rifabutin had MICs of 3 ± 2 μM (3 μg/ml) against the screening strain, the reference strains M. abscessus subsp. abscessus ATCC 19977, M. abscessus subsp. bolletii CCUG 50184-T, and M. abscessus subsp. massiliense CCUG 48898-T, as well as against a collection of clinical isolates. Furthermore, rifabutin was active against clarithromycin-resistant strains. In conclusion, rifabutin, in contrast to rifampin, is active against the Mycobacterium abscessus complex bacteria in vitro and may be considered for treatment of M. abscessus lung disease.
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