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Thomas J, Mokkawes T, Senft L, Dey A, Gordon JB, Ivanovic-Burmazovic I, de Visser SP, Goldberg DP. Axial Ligation Impedes Proton-Coupled Electron-Transfer Reactivity of a Synthetic Compound-I Analogue. J Am Chem Soc 2024; 146:12338-12354. [PMID: 38669456 DOI: 10.1021/jacs.3c08950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
The nature of the axial ligand in high-valent iron-oxo heme enzyme intermediates and related synthetic catalysts is a critical structural element for controlling proton-coupled electron-transfer (PCET) reactivity of these species. Herein, we describe the generation and characterization of three new 6-coordinate, iron(IV)-oxo porphyrinoid-π-cation-radical complexes and report their PCET reactivity together with a previously published 5-coordinate analogue, FeIV(O)(TBP8Cz+•) (TBP8Cz = octakis(p-tert-butylphenyl)corrolazinato3-) (2) (Cho, K. A high-valent iron-oxo corrolazine activates C-H bonds via hydrogen-atom transfer. J. Am. Chem. Soc. 2012, 134, 7392-7399). The new complexes FeIV(O)(TBP8Cz+•)(L) (L = 1-methyl imidazole (1-MeIm) (4a), 4-dimethylaminopyridine (DMAP) (4b), cyanide (CN-)(4c)) can be generated from either oxidation of the ferric precursors or by addition of L to the Compound-I (Cpd-I) analogue at low temperatures. These complexes were characterized by UV-vis, electron paramagnetic resonance (EPR), and Mössbauer spectroscopies, and cryospray ionization mass spectrometry (CSI-MS). Kinetic studies using 4-OMe-TEMPOH as a test substrate indicate that coordination of a sixth axial ligand dramatically lowers the PCET reactivity of the Cpd-I analogue (rates up to 7000 times slower). Extensive density functional theory (DFT) calculations together with the experimental data show that the trend in reactivity with the axial ligands does not correlate with the thermodynamic driving force for these reactions or the calculated strengths of the O-H bonds being formed in the FeIV(O-H) products, pointing to non-Bell-Evans-Polanyi behavior. However, the PCET reactivity does follow a trend with the bracketed reduction potential of Cpd-I analogues and calculated electron affinities. The combined data suggest a concerted mechanism (a concerted proton electron transfer (CPET)) and an asynchronous movement of the electron/proton pair in the transition state.
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Affiliation(s)
- Jithin Thomas
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Thirakorn Mokkawes
- The Manchester Institute of Biotechnology and Department of Chemical Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Laura Senft
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr., 5-13, Haus D, 81377 München, Germany
| | - Aniruddha Dey
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Jesse B Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Ivana Ivanovic-Burmazovic
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr., 5-13, Haus D, 81377 München, Germany
| | - Sam P de Visser
- The Manchester Institute of Biotechnology and Department of Chemical Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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2
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Lučić M, Wilson MT, Pullin J, Hough MA, Svistunenko DA, Worrall JAR. New insights into controlling radical migration pathways in heme enzymes gained from the study of a dye-decolorising peroxidase. Chem Sci 2023; 14:12518-12534. [PMID: 38020392 PMCID: PMC10646903 DOI: 10.1039/d3sc04453j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/06/2023] [Indexed: 12/01/2023] Open
Abstract
In heme enzymes, such as members of the dye-decolorising peroxidase (DyP) family, the formation of the highly oxidising catalytic Fe(iv)-oxo intermediates following reaction with hydrogen peroxide can lead to free radical migration (hole hopping) from the heme to form cationic tyrosine and/or tryptophan radicals. These species are highly oxidising (∼1 V vs. NHE) and under certain circumstances can catalyse the oxidation of organic substrates. Factors that govern which specific tyrosine or tryptophan the free radical migrates to in heme enzymes are not well understood, although in the case of tyrosyl radical formation the nearby proximity of a proton acceptor is a recognised facilitating factor. By using an A-type member of the DyP family (DtpAa) as an exemplar, we combine protein engineering, X-ray crystallography, hole-hopping calculations, EPR spectroscopy and kinetic modelling to provide compelling new insights into the control of radical migration pathways following reaction of the heme with hydrogen peroxide. We demonstrate that the presence of a tryptophan/tyrosine dyad motif displaying a T-shaped orientation of aromatic rings on the proximal side of the heme dominates the radical migration landscape in wild-type DtpAa and continues to do so following the rational engineering into DtpAa of a previously identified radical migration pathway in an A-type homolog on the distal side of the heme. Only on disrupting the proximal dyad, through removal of an oxygen atom, does the radical migration pathway then switch to the engineered distal pathway to form the desired tyrosyl radical. Implications for protein design and biocatalysis are discussed.
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Affiliation(s)
- Marina Lučić
- School of Life Sciences, University of Essex Wivenhoe Park Colchester Essex CO4 3SQ UK
| | - Michael T Wilson
- School of Life Sciences, University of Essex Wivenhoe Park Colchester Essex CO4 3SQ UK
| | - Jacob Pullin
- School of Life Sciences, University of Essex Wivenhoe Park Colchester Essex CO4 3SQ UK
| | - Michael A Hough
- School of Life Sciences, University of Essex Wivenhoe Park Colchester Essex CO4 3SQ UK
- Diamond Light Source, Harwell Science and Innovation Campus Didcot Oxfordshire OX11 0DE UK
| | - Dimitri A Svistunenko
- School of Life Sciences, University of Essex Wivenhoe Park Colchester Essex CO4 3SQ UK
| | - Jonathan A R Worrall
- School of Life Sciences, University of Essex Wivenhoe Park Colchester Essex CO4 3SQ UK
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3
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Palomino A, Gewurz D, DeVine L, Zajmi U, Moralez J, Abu-Rumman F, Smith RP, Lopatkin AJ. Metabolic genes on conjugative plasmids are highly prevalent in Escherichia coli and can protect against antibiotic treatment. ISME J 2023; 17:151-162. [PMID: 36261510 PMCID: PMC9750983 DOI: 10.1038/s41396-022-01329-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 09/21/2022] [Accepted: 09/28/2022] [Indexed: 12/15/2022]
Abstract
Conjugative plasmids often encode antibiotic resistance genes that provide selective advantages to their bacterial hosts during antibiotic treatment. Previous studies have predominantly considered these established genes as the primary benefit of antibiotic-mediated plasmid dissemination. However, many genes involved in cellular metabolic processes may also protect against antibiotic treatment and provide selective advantages. Despite the diversity of such metabolic genes and their potential ecological impact, their plasmid-borne prevalence, co-occurrence with canonical antibiotic resistance genes, and phenotypic effects remain widely understudied. To address this gap, we focused on Escherichia coli, which can often act as a pathogen, and is known to spread antibiotic resistance genes via conjugation. We characterized the presence of metabolic genes on 1,775 transferrable plasmids and compared their distribution to that of known antibiotic resistance genes. We found high abundance of genes involved in cellular metabolism and stress response. Several of these genes demonstrated statistically significant associations or disassociations with known antibiotic resistance genes at the strain level, indicating that each gene type may impact the spread of the other across hosts. Indeed, in vitro characterization of 13 statistically relevant metabolic genes confirmed that their phenotypic impact on antibiotic susceptibility was largely consistent with in situ relationships. These results emphasize the ecological importance of metabolic genes on conjugal plasmids, and that selection dynamics of E. coli pathogens arises as a complex consequence of both canonical mechanisms and their interactions with metabolic pathways.
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Affiliation(s)
- Alana Palomino
- grid.470930.90000 0001 2182 2351Department of Biology, Barnard College, New York, NY 10027 USA
| | - Danya Gewurz
- grid.470930.90000 0001 2182 2351Department of Biology, Barnard College, New York, NY 10027 USA
| | - Lela DeVine
- grid.470930.90000 0001 2182 2351Department of Biology, Barnard College, New York, NY 10027 USA
| | - Ujana Zajmi
- grid.470930.90000 0001 2182 2351Department of Biology, Barnard College, New York, NY 10027 USA
| | - Jenifer Moralez
- grid.470930.90000 0001 2182 2351Department of Biology, Barnard College, New York, NY 10027 USA
| | - Fatima Abu-Rumman
- grid.261241.20000 0001 2168 8324Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314 USA
| | - Robert P. Smith
- grid.261241.20000 0001 2168 8324Department of Biological Sciences, Halmos College of Arts and Science, Nova Southeastern University, Fort Lauderdale, FL 33314 USA ,grid.261241.20000 0001 2168 8324Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL 33314 USA
| | - Allison J. Lopatkin
- grid.470930.90000 0001 2182 2351Department of Biology, Barnard College, New York, NY 10027 USA ,grid.21729.3f0000000419368729Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY 10027 USA ,grid.21729.3f0000000419368729Data Science Institute, Columbia University, New York, NY 10027 USA ,grid.21729.3f0000000419368729Department of Systems Biology, Columbia University, New York, NY 10027 USA ,grid.16416.340000 0004 1936 9174Department of Chemical Engineering, University of Rochester, Rochester, NY 14627 USA
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4
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Yang Y, Lu Z, Azari M, Kartal B, Du H, Cai M, Herbold CW, Ding X, Denecke M, Li X, Li M, Gu JD. Discovery of a new genus of anaerobic ammonium oxidizing bacteria with a mechanism for oxygen tolerance. Water Res 2022; 226:119165. [PMID: 36257158 DOI: 10.1016/j.watres.2022.119165] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 09/15/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
In the past 20 years, there has been a major stride in understanding the core mechanism of anaerobic ammonium-oxidizing (anammox) bacteria, but there are still several discussion points on their survival strategies. Here, we discovered a new genus of anammox bacteria in a full-scale wastewater-treating biofilm system, tentatively named "Candidatus Loosdrechtia aerotolerans". Next to genes of all core anammox metabolisms, it encoded and transcribed genes involved in the dissimilatory nitrate reduction to ammonium (DNRA), which coupled to oxidation of small organic acids, could be used to replenish ammonium and sustain their metabolism. Surprisingly, it uniquely harbored a new ferredoxin-dependent nitrate reductase, which has not yet been found in any other anammox genome and might confer a selective advantage to it in nitrate assimilation. Similar to many other microorganisms, superoxide dismutase and catalase related to oxidative stress resistance were encoded and transcribed by "Ca. Loosdrechtia aerotolerans". Interestingly, bilirubin oxidase (BOD), likely involved in oxygen resistance of anammox bacteria under fluctuating oxygen concentrations, was identified in "Ca. Loosdrechtia aerotolerans" and four Ca. Brocadia genomes, and its activity was demonstrated using purified heterologously expressed proteins. A following survey of oxygen-active proteins in anammox bacteria revealed the presence of other previously undetected oxygen defense systems. The novel cbb3-type cytochrome c oxidase and bifunctional catalase-peroxidase may confer a selective advantage to Ca. Kuenenia and Ca. Scalindua that face frequent changes in oxygen concentrations. The discovery of this new genus significantly broadens our understanding of the ecophysiology of anammox bacteria. Furthermore, the diverse oxygen tolerance strategies employed by distinct anammox bacteria advance our understanding of their niche adaptability and provide valuable insight for the operation of anammox-based wastewater treatment systems.
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Affiliation(s)
- Yuchun Yang
- State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-Sen University, Guangzhou 510275, People's Republic of China
| | - Zhongyi Lu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, People's Republic of China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Mohammad Azari
- Department of Aquatic Environmental Engineering, Institute for Water and River Basin Management, Karlsruhe Institute of Technology (KIT), Gotthard-Franz-Str. 3, Karlsruhe 76131, Germany
| | - Boran Kartal
- Microbial Physiology Group, Max Planck Institute for Marine Microbiology, Celsiusstraße 1, Bremen 28359, Germany
| | - Huan Du
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Mingwei Cai
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Craig W Herbold
- Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria
| | - Xinghua Ding
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
| | - Martin Denecke
- Department of Urban Water- and Waste Management, University of Duisburg-Essen, Universitätsstraße 15, Essen 45141, Germany
| | - Xiaoyan Li
- Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
| | - Meng Li
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Ji-Dong Gu
- Environmental Science and Engineering Research Group, Guangdong Technion - Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, People's Republic of China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, Guangdong 519082, People's Republic of China; Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion, Guangdong Technion - Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, People's Republic of China.
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5
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Barozi V, Musyoka TM, Sheik Amamuddy O, Tastan Bishop Ö. Deciphering Isoniazid Drug Resistance Mechanisms on Dimeric Mycobacterium tuberculosis KatG via Post-molecular Dynamics Analyses Including Combined Dynamic Residue Network Metrics. ACS Omega 2022; 7:13313-13332. [PMID: 35474779 PMCID: PMC9025985 DOI: 10.1021/acsomega.2c01036] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 03/22/2022] [Indexed: 05/12/2023]
Abstract
Resistance mutations in Mycobacterium tuberculosis (Mtb) catalase peroxidase protein (KatG), an essential enzyme in isoniazid (INH) activation, reduce the sensitivity of Mtb to first-line drugs, hence presenting challenges in tuberculosis (TB) management. Thus, understanding the mutational imposed resistance mechanisms remains of utmost importance in the quest to reduce the TB burden. Herein, effects of 11 high confidence mutations in the KatG structure and residue network communication patterns were determined using extensive computational approaches. Combined traditional post-molecular dynamics analysis and comparative essential dynamics revealed that the mutant proteins have significant loop flexibility around the heme binding pocket and enhanced asymmetric protomer behavior with respect to wild-type (WT) protein. Heme contact analysis between WT and mutant proteins identified a reduction to no contact between heme and residue His270, a covalent bond vital for the heme-enabled KatG catalytic activity. Betweenness centrality calculations showed large hub ensembles with new hubs especially around the binding cavity and expanded to the dimerization domain via interface in the mutant systems, providing possible compensatory allosteric communication paths for the active site as a result of the mutations which may destabilize the heme binding pocket and the loops in its vicinity. Additionally, an interesting observation came from Eigencentrality hubs, most of which are located in the C-terminal domain, indicating relevance of the domain in the protease functionality. Overall, our results provide insight toward the mechanisms involved in KatG-INH resistance in addition to identifying key regions in the enzyme functionality, which can be used for future drug design.
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Affiliation(s)
- Victor Barozi
- Research Unit in Bioinformatics
(RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6140 South Africa
| | - Thommas Mutemi Musyoka
- Research Unit in Bioinformatics
(RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6140 South Africa
| | - Olivier Sheik Amamuddy
- Research Unit in Bioinformatics
(RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6140 South Africa
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics
(RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6140 South Africa
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6
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Wan F, Feng X, Yin J, Gao H. Distinct H 2O 2-Scavenging System in Yersinia pseudotuberculosis: KatG and AhpC Act Together to Scavenge Endogenous Hydrogen Peroxide. Front Microbiol 2021; 12:626874. [PMID: 34025596 PMCID: PMC8139631 DOI: 10.3389/fmicb.2021.626874] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 03/22/2021] [Indexed: 01/09/2023] Open
Abstract
To colonize in the digestive tract of animals and humans, Yersinia pseudotuberculosis has to deal with reactive oxygen species (ROS) produced by host cells and microbiota. However, an understanding of the ROS-scavenging systems and their regulation in this bacterium remains largely elusive. In this study, we identified OxyR as the master transcriptional regulator mediating cellular responses to hydrogen peroxide (H2O2) in Y. pseudotuberculosis through genomics and transcriptomics analyses. OxyR activates transcription of diverse genes, especially the core members of its regulon, including those encoding catalases, peroxidases, and thiol reductases. The data also suggest that sulfur species and manganese may play a particular role in the oxidative stress response of Y. pseudotuberculosis. Among the three H2O2-scavenging systems in Y. pseudotuberculosis, catalase/peroxidase KatE functions as the primary scavenger for high levels of H2O2; NADH peroxidase alkyl hydroperoxide reductase (AhpR) and catalase KatG together are responsible for removing low levels of H2O2. The simultaneous loss of both AhpC (the peroxidatic component of AhpR) and KatG results in activation of OxyR. Moreover, we found that AhpC, unlike its well-characterized Escherichia coli counterpart, has little effect on protecting cells against toxicity of organic peroxides. These findings provide not only novel insights into the structural and functional diversity of bacterial H2O2-scavenging systems but also a basic understanding of how Y. pseudotuberculosis copes with oxidative stress.
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Affiliation(s)
- Fen Wan
- College of Laboratory Medicine, Hangzhou Medical College, Hangzhou, China
| | - Xue Feng
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhenjiang University of Technology, Hangzhou, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
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7
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Al-Attar R, Storey KB. RAGE against the stress: Mitochondrial suppression in hypometabolic hearts. Gene 2020; 761:145039. [PMID: 32777527 DOI: 10.1016/j.gene.2020.145039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/19/2020] [Accepted: 08/04/2020] [Indexed: 12/22/2022]
Abstract
The wood frog (Rana sylvatica) can tolerate full body freezing in winter. As a protective response, wood frogs dehydrate their cells and accumulate large quantities of glucose as an intracellular cryoprotectant. Freezing causes ischemia since blood delivery to organs is interrupted. Fascinatingly, wood frogs can tolerate dehydration, extreme hyperglycemia, and anoxia independently of freezing. In response to low oxygen levels, wood frogs strategically reduce their metabolic rates and allocate the finite amount of intracellular fuel available to pro-survival processes while reducing or interrupting all others. In this study, the involvement of advanced glycation end products (AGEs) and the high mobility group box 1 (HMGB1) protein in activating RAGE (AGE receptor) were investigated. The results show that freezing, anoxia and dehydration induced the expression of total HMGB1 and its acetylation in the heart. RAGE levels were induced in response to all stress conditions, which resulted in differential regulation of the ETS1 transcription factor. While the nuclear localization of total ETS1 was not affected, the DNA binding activity of total and its active form increased in response to freezing and dehydration but not in response to anoxia. Current results indicate that ETS1 acts as a transcriptional activator for peroxiredoxin 1 in response to freezing but acts as a transcriptional repressor of several nuclear-encoded mitochondrial genes in response to all stresses. Altogether, current results show that the HMGB1/RAGE axis may activate ETS1 and that this activation could result in both transcriptional activation and/or repression in a stress-dependent manner.
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Affiliation(s)
- Rasha Al-Attar
- Institude of Biochemistry and Department of Biology, Carleton University, Ottawa, ON K1S-5B6, Canada
| | - Kenneth B Storey
- Institude of Biochemistry and Department of Biology, Carleton University, Ottawa, ON K1S-5B6, Canada.
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8
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in 't Zandt MH, Frank J, Yilmaz P, Cremers G, Jetten MSM, Welte CU. Long-term enriched methanogenic communities from thermokarst lake sediments show species-specific responses to warming. FEMS Microbes 2020; 1:xtaa008. [PMID: 37333957 PMCID: PMC10117432 DOI: 10.1093/femsmc/xtaa008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/14/2020] [Indexed: 04/05/2024] Open
Abstract
Thermokarst lakes are large potential greenhouse gas (GHG) sources in a changing Arctic. In a warming world, an increase in both organic matter availability and temperature is expected to boost methanogenesis and potentially alter the microbial community that controls GHG fluxes. These community shifts are, however, challenging to detect by resolution-limited 16S rRNA gene-based approaches. Here, we applied full metagenome sequencing on long-term thermokarst lake sediment enrichments on acetate and trimethylamine at 4°C and 10°C to unravel species-specific responses to the most likely Arctic climate change scenario. Substrate amendment was used to mimic the increased organic carbon availability upon permafrost thaw. By performing de novo assembly, we reconstructed five high-quality and five medium-quality metagenome-assembled genomes (MAGs) that represented 59% of the aligned metagenome reads. Seven bacterial MAGs belonged to anaerobic fermentative bacteria. Within the Archaea, the enrichment of methanogenic Methanosaetaceae/Methanotrichaceae under acetate amendment and Methanosarcinaceae under trimethylamine (TMA) amendment was not unexpected. Surprisingly, we observed temperature-specific methanogenic (sub)species responses with TMA amendment. These highlighted distinct and potentially functional climate-induced shifts could not be revealed with 16S rRNA gene-based analyses. Unraveling these temperature- and nutrient-controlled species-level responses is essential to better comprehend the mechanisms that underlie GHG production from Arctic lakes in a warming world.
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Affiliation(s)
- Michiel H in 't Zandt
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
- Netherlands Earth System Science Centre, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, the Netherlands
| | - Jeroen Frank
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
- Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Polen Yilmaz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Geert Cremers
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
- Netherlands Earth System Science Centre, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, the Netherlands
- Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Cornelia U Welte
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
- Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
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9
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Abstract
Bacteria display an array of enzymes to detoxify reactive oxygen species that cause damage to DNA and to other biomolecules leading to cell death. Hydrogen peroxide is one of these species, with endogenous and exogenous sources, such as lactic acid bacteria, oxidative burst of the immune system or chemical reactions at oxic-anoxic interfaces. The enzymes that detoxify hydrogen peroxide will be the focus of this review, with special emphasis on bacterial peroxidases that reduce hydrogen peroxide to water. Bacterial peroxidases are periplasmic cytochromes with either two or three c-type haems, which have been classified as classical and non-classical bacterial peroxidases, respectively. Most of the studies have been focus on the classical bacterial peroxidases, showing the presence of a reductive activation in the presence of calcium ions. Mutagenesis studies have clarified the catalytic mechanism of this enzyme and were used to propose an intramolecular electron transfer pathway, with far less being known about the intermolecular electron transfer that occurs between reduced electron donors and the enzyme. The physiological function of these enzymes was not very clear until it was shown, for the non-classical bacterial peroxidase, that this enzyme is required for the bacteria to use hydrogen peroxide as terminal electron acceptor under anoxic conditions. These non-classical bacterial peroxidases are quinol peroxidases that do not require reductive activation but need calcium ions to attain maximum activity and share similar catalytic intermediates with the classical bacterial peroxidases.
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Affiliation(s)
- Cláudia S Nóbrega
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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Możejko-Ciesielska J, Mostek A. Time-Course Proteomic Analysis of Pseudomonas putida KT2440 during Mcl-Polyhydroxyalkanoate Synthesis under Nitrogen Deficiency. Polymers (Basel) 2019; 11:polym11050748. [PMID: 31035475 PMCID: PMC6571654 DOI: 10.3390/polym11050748] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 04/19/2019] [Accepted: 04/23/2019] [Indexed: 11/05/2022] Open
Abstract
Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) have gained great attention as a new green alternative to petrochemical-derived polymers. Due to their outstanding material properties they can be used in a wide range of applications. Pseudomonas putida KT2440 is a metabolically versatile producer of mcl-polyhydroxyalkanoates. Although the metabolism of polyhydroxyalkanoate synthesis by this bacterium has been extensively studied, the comparative proteome analysis from three growth stages of Pseudomonas putida KT2440 cultured with oleic acid during mcl-PHA synthesis has not yet been reported. Therefore; the aim of the study was to compare the proteome of Pseudomonas putida KT2440 at different time points of its cultivation using the 2D difference gel electrophoresis (2D-DIGE) technique. The analyses showed that low levels of a nitrogen source were beneficial for mcl-PHA synthesis. Proteomic analysis revealed that the proteins associated with carbon metabolism were affected by nitrogen starvation and mcl-PHA synthesis. Furthermore, the induction of proteins involved in nitrogen metabolism, ribosome synthesis, and transport was observed, which may be the cellular response to stress related to nitrogen deficiency and mcl-PHA content in bacterial cells. To sum up; this study enabled the investigators to acquire a better knowledge of the molecular mechanisms underlying the induction of polyhydroxyalkanoate synthesis and accumulation in Pseudomonas putida KT2440 that could lead to improved strategies for PHAs in industrial production.
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Affiliation(s)
- Justyna Możejko-Ciesielska
- Department of Microbiology and Mycology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10719 Olsztyn, Poland.
| | - Agnieszka Mostek
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, Tuwima 10, 10748 Olsztyn, Poland.
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11
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Chaplin AK, Chicano TM, Hampshire BV, Wilson MT, Hough MA, Svistunenko DA, Worrall JAR. An Aromatic Dyad Motif in Dye Decolourising Peroxidases Has Implications for Free Radical Formation and Catalysis. Chemistry 2019; 25:6141-6153. [PMID: 30945782 DOI: 10.1002/chem.201806290] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Indexed: 01/27/2023]
Abstract
Dye decolouring peroxidases (DyPs) are the most recent class of heme peroxidase to be discovered. On reacting with H2 O2 , DyPs form a high-valent iron(IV)-oxo species and a porphyrin radical (Compound I) followed by stepwise oxidation of an organic substrate. In the absence of substrate, the ferryl species decays to form transient protein-bound radicals on redox active amino acids. Identification of radical sites in DyPs has implications for their oxidative mechanism with substrate. Using a DyP from Streptomyces lividans, referred to as DtpA, which displays low reactivity towards synthetic dyes, activation with H2 O2 was explored. A Compound I EPR spectrum was detected, which in the absence of substrate decays to a protein-bound radical EPR signal. Using a newly developed version of the Tyrosyl Radical Spectra Simulation Algorithm, the radical EPR signal was shown to arise from a pristine tyrosyl radical and not a mixed Trp/Tyr radical that has been widely reported in DyP members exhibiting high activity with synthetic dyes. The radical site was identified as Tyr374, with kinetic studies inferring that although Tyr374 is not on the electron-transfer pathway from the dye RB19, its replacement with a Phe does severely compromise activity with other organic substrates. These findings hint at the possibility that alternative electron-transfer pathways for substrate oxidation are operative within the DyP family. In this context, a role for a highly conserved aromatic dyad motif is discussed.
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Affiliation(s)
- Amanda K Chaplin
- Present address: Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Tadeo Moreno Chicano
- Present address: Department of Molecular Mechanisms, Max Planck Institute for Medical Research, Jahnstraße 29, 69120, Heidelberg, Germany
| | - Bethany V Hampshire
- Present address: Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Michael T Wilson
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Michael A Hough
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Dimitri A Svistunenko
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Jonathan A R Worrall
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
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12
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Wang B, Fita I, Rovira C. Theory Uncovers the Role of the Methionine-Tyrosine-Tryptophan Radical Adduct in the Catalase Reaction of KatGs: O2
Release Mediated by Proton-Coupled Electron Transfer. Chemistry 2018; 24:5388-5395. [DOI: 10.1002/chem.201706076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Binju Wang
- Departament de Química Inorgànica i Orgànica, (secció de Química Orgànica) &, Institut de Química Teòrica i Computacional (IQTCUB); Universitat de Barcelona; Martí i Franquès 1 08028 Barcelona Spain
| | - Ignacio Fita
- Instituto de Biología Molecular (IBMB-CSIC) and; Maria de Maeztu Unit of Excellence. Barcelona Science Park; Baldiri i Reixac 10. 08028 Barcelona Spain
| | - Carme Rovira
- Departament de Química Inorgànica i Orgànica, (secció de Química Orgànica) &, Institut de Química Teòrica i Computacional (IQTCUB); Universitat de Barcelona; Martí i Franquès 1 08028 Barcelona Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA); Passeig Lluís Companys 23 08010 Barcelona Spain
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13
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Nóbrega CS, Devreese B, Pauleta SR. YhjA - An Escherichia coli trihemic enzyme with quinol peroxidase activity. Biochim Biophys Acta Bioenerg 2018; 1859:411-422. [PMID: 29550214 DOI: 10.1016/j.bbabio.2018.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/11/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
Abstract
The trihemic bacterial cytochrome c peroxidase from Escherichia coli, YhjA, is a membrane-anchored protein with a C-terminal domain homologous to the classical bacterial peroxidases and an additional N-terminal (NT) heme binding domain. Recombinant YhjA is a 50 kDa monomer in solution with three c-type hemes covalently bound. Here is reported the first biochemical and spectroscopic characterization of YhjA and of the NT domain demonstrating that NT heme is His63/Met125 coordinated. The reduction potentials of P (active site), NT and E hemes were established to be -170 mV, +133 mV and +210 mV, respectively, at pH 7.5. YhjA has quinol peroxidase activity in vitro with optimum activity at pH 7.0 and millimolar range KM values using hydroquinone and menadiol (a menaquinol analogue) as electron donors (KM = 0.6 ± 0.2 and 1.8 ± 0.5 mM H2O2, respectively), with similar turnover numbers (kcat = 19 ± 2 and 13 ± 2 s-1, respectively). YhjA does not require reductive activation for maximum activity, in opposition to classical bacterial peroxidases, as P heme is always high-spin 6-coordinated with a water-derived molecule as distal axial ligand but shares the need for the presence of calcium ions in the kinetic assays. Formation of a ferryl Fe(IV) = O species was observed upon incubation of fully oxidized YhjA with H2O2. The data reported improve our understanding of the biochemical properties and catalytic mechanism of YhjA, a three-heme peroxidase that uses the quinol pool to defend the cells against hydrogen peroxide during transient exposure to oxygenated environments.
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Affiliation(s)
- Cláudia S Nóbrega
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
| | - Bart Devreese
- Laboratory of Protein Biochemistry and Biomolecular Engineering, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
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14
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Njuma OJ, Davis I, Ndontsa EN, Krewall JR, Liu A, Goodwin DC. Mutual synergy between catalase and peroxidase activities of the bifunctional enzyme KatG is facilitated by electron hole-hopping within the enzyme. J Biol Chem 2017; 292:18408-18421. [PMID: 28972181 DOI: 10.1074/jbc.m117.791202] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 09/22/2017] [Indexed: 11/06/2022] Open
Abstract
KatG is a bifunctional, heme-dependent enzyme in the front-line defense of numerous bacterial and fungal pathogens against H2O2-induced oxidative damage from host immune responses. Contrary to the expectation that catalase and peroxidase activities should be mutually antagonistic, peroxidatic electron donors (PxEDs) enhance KatG catalase activity. Here, we establish the mechanism of synergistic cooperation between these activities. We show that at low pH values KatG can fully convert H2O2 to O2 and H2O only if a PxED is present in the reaction mixture. Stopped-flow spectroscopy results indicated rapid initial rates of H2O2 disproportionation slowing concomitantly with the accumulation of ferryl-like heme states. These states very slowly returned to resting (i.e. ferric) enzyme, indicating that they represented catalase-inactive intermediates. We also show that an active-site tryptophan, Trp-321, participates in off-pathway electron transfer. A W321F variant in which the proximal tryptophan was replaced with a non-oxidizable phenylalanine exhibited higher catalase activity and less accumulation of off-pathway heme intermediates. Finally, rapid freeze-quench EPR experiments indicated that both WT and W321F KatG produce the same methionine-tyrosine-tryptophan (MYW) cofactor radical intermediate at the earliest reaction time points and that Trp-321 is the preferred site of off-catalase protein oxidation in the native enzyme. Of note, PxEDs did not affect the formation of the MYW cofactor radical but could reduce non-productive protein-based radical species that accumulate during reaction with H2O2 Our results suggest that catalase-inactive intermediates accumulate because of off-mechanism oxidation, primarily of Trp-321, and PxEDs stimulate KatG catalase activity by preventing the accumulation of inactive intermediates.
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Affiliation(s)
- Olive J Njuma
- From the Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312
| | - Ian Davis
- the Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249-0698, and.,the Department of Chemistry, Georgia State University, Atlanta, Georgia 30303
| | - Elizabeth N Ndontsa
- From the Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312
| | - Jessica R Krewall
- From the Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312
| | - Aimin Liu
- the Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249-0698, and
| | - Douglas C Goodwin
- From the Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312,
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15
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Teder T, Lõhelaid H, Samel N. Structural and functional insights into the reaction specificity of catalase-related hydroperoxide lyase: A shift from lyase activity to allene oxide synthase by site-directed mutagenesis. PLoS One 2017; 12:e0185291. [PMID: 28953966 DOI: 10.1371/journal.pone.0185291] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/08/2017] [Indexed: 11/22/2022] Open
Abstract
Two highly identical fusion proteins, an allene oxide synthase-lipoxygenase (AOS-LOX) and a hydroperoxide lyase-lipoxygenase (HPL-LOX), were identified in the soft coral Capnella imbricata. Both enzymes initially catalyze the formation of 8R-hydroperoxy-eicosatetraenoic acid (8R-HpETE) from arachidonic acid by the C-terminal lipoxygenase (LOX) domain. Despite the fact that the defined catalytically important residues of N-terminal catalase-related allene oxide synthase (cAOS) domain are also conserved in C. imbricata hydroperoxide lyase (cHPL), their reaction specificities differ. In the present study, we tested which of the amino acid substitutions around the active site of cHPL are responsible for a control in the reaction specificity. The possible candidates were determined via comparative sequence and structural analysis of the substrate channel and the heme region of coral cAOSs and C. imbricata cHPL. The amino acid replacements in cHPL—R56G, ME59-60LK, P65A, F150L, YS176-177NL, I357V, and SSSAGE155-160PVKEGD—with the corresponding residues of cAOS were conducted by site-directed mutagenesis. Although all these mutations influenced the catalytic efficiency of cHPL, only F150L and YS176-177NL substitutions caused a shift in the reaction specificity from HPL to AOS. The docking analysis of P. homomalla cAOS with 8R-HpETE substrate revealed that the Leu150 of cAOS interacts with the C5-C6 double bond and the Leu177 with the hydrophobic tail of 8R-HpETE. We propose that the corresponding residues in cHPL, Phe150 and Ser177, are involved in a proper coordination of the epoxy allylic radical intermediate necessary for aldehyde formation in the hydroperoxide lyase reaction.
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16
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Nguyen GT, Green ER, Mecsas J. Neutrophils to the ROScue: Mechanisms of NADPH Oxidase Activation and Bacterial Resistance. Front Cell Infect Microbiol 2017; 7:373. [PMID: 28890882 PMCID: PMC5574878 DOI: 10.3389/fcimb.2017.00373] [Citation(s) in RCA: 418] [Impact Index Per Article: 59.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/02/2017] [Indexed: 12/16/2022] Open
Abstract
Reactive oxygen species (ROS) generated by NADPH oxidase play an important role in antimicrobial host defense and inflammation. Their deficiency in humans results in recurrent and severe bacterial infections, while their unregulated release leads to pathology from excessive inflammation. The release of high concentrations of ROS aids in clearance of invading bacteria. Localization of ROS release to phagosomes containing pathogens limits tissue damage. Host immune cells, like neutrophils, also known as PMNs, will release large amounts of ROS at the site of infection following the activation of surface receptors. The binding of ligands to G-protein-coupled receptors (GPCRs), toll-like receptors, and cytokine receptors can prime PMNs for a more robust response if additional signals are encountered. Meanwhile, activation of Fc and integrin directly induces high levels of ROS production. Additionally, GPCRs that bind to the bacterial-peptide analog fMLP, a neutrophil chemoattractant, can both prime cells and trigger low levels of ROS production. Engagement of these receptors initiates intracellular signaling pathways, resulting in activation of downstream effector proteins, assembly of the NADPH oxidase complex, and ultimately, the production of ROS by this complex. Within PMNs, ROS released by the NADPH oxidase complex can activate granular proteases and induce the formation of neutrophil extracellular traps (NETs). Additionally, ROS can cross the membranes of bacterial pathogens and damage their nucleic acids, proteins, and cell membranes. Consequently, in order to establish infections, bacterial pathogens employ various strategies to prevent restriction by PMN-derived ROS or downstream consequences of ROS production. Some pathogens are able to directly prevent the oxidative burst of phagocytes using secreted effector proteins or toxins that interfere with translocation of the NADPH oxidase complex or signaling pathways needed for its activation. Nonetheless, these pathogens often rely on repair and detoxifying proteins in addition to these secreted effectors and toxins in order to resist mammalian sources of ROS. This suggests that pathogens have both intrinsic and extrinsic mechanisms to avoid restriction by PMN-derived ROS. Here, we review mechanisms of oxidative burst in PMNs in response to bacterial infections, as well as the mechanisms by which bacterial pathogens thwart restriction by ROS to survive under conditions of oxidative stress.
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Affiliation(s)
- Giang T Nguyen
- Graduate Program in Immunology, Sackler School of Graduate Biomedical Sciences, Tufts UniversityBoston, MA, United States
| | - Erin R Green
- Department of Molecular Biology and Microbiology, Tufts University School of MedicineBoston, MA, United States
| | - Joan Mecsas
- Graduate Program in Immunology, Sackler School of Graduate Biomedical Sciences, Tufts UniversityBoston, MA, United States.,Department of Molecular Biology and Microbiology, Tufts University School of MedicineBoston, MA, United States
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17
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Sun D, Crowell SA, Harding CM, De Silva PM, Harrison A, Fernando DM, Mason KM, Santana E, Loewen PC, Kumar A, Liu Y. KatG and KatE confer Acinetobacter resistance to hydrogen peroxide but sensitize bacteria to killing by phagocytic respiratory burst. Life Sci 2016; 148:31-40. [PMID: 26860891 DOI: 10.1016/j.lfs.2016.02.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 01/28/2016] [Accepted: 02/05/2016] [Indexed: 02/05/2023]
Abstract
AIMS Catalase catalyzes the degradation of H2O2. Acinetobacter species have four predicted catalase genes, katA, katE, katG, and katX. The aims of the present study seek to determine which catalase(s) plays a predominant role in determining the resistance to H2O2, and to assess the role of catalase in Acinetobacter virulence. MAIN METHODS Mutants of Acinetobacter baumannii and Acinetobacter nosocomialis with deficiencies in katA, katE, katG, and katX were tested for sensitivity to H2O2, either by halo assays or by liquid culture assays. Respiratory burst of neutrophils, in response to A. nosocomialis, was assessed by chemiluminescence to examine the effects of catalase on the production of reactive oxygen species (ROS) in neutrophils. Bacterial virulence was assessed using a Galleria mellonella larva infection model. KEY FINDINGS The capacities of A. baumannii and A. nosocomialis to degrade H2O2 are largely dependent on katE. The resistance of both A. baumannii and A. nosocomialis to H2O2 is primarily determined by the katG gene, although katE also plays a minor role in H2O2 resistance. Bacteria lacking both the katG and katE genes exhibit the highest sensitivity to H2O2. While A. nosocomialis bacteria with katE and/or katG were able to decrease ROS production by neutrophils, these cells also induced a more robust respiratory burst in neutrophils than did cells deficient in both katE and katG. We also found that A. nosocomialis deficient in both katE and katG was more virulent than the wildtype A. nosocomialis strain. SIGNIFICANCE Our findings suggest that inhibition of Acinetobacter catalase may help to overcome the resistance of Acinetobacter species to microbicidal H2O2 and facilitate bacterial disinfection.
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Affiliation(s)
- Daqing Sun
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Surgery, The Second Hospital of Shandong University, Jinan, Shandong, China
| | - Sara A Crowell
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Christian M Harding
- Center of Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - P Malaka De Silva
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Alistair Harrison
- Center of Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Dinesh M Fernando
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kevin M Mason
- Center of Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Estevan Santana
- Center of Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Peter C Loewen
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ayush Kumar
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Medical Microbiology, College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Yusen Liu
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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18
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Broden NJ, Flury S, King AN, Schroeder BW, Coe GD, Faulkner MJ. Insights into the Function of a Second, Nonclassical Ahp Peroxidase, AhpA, in Oxidative Stress Resistance in Bacillus subtilis. J Bacteriol 2016; 198:1044-57. [PMID: 26787766 DOI: 10.1128/JB.00679-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 01/12/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Organisms growing aerobically generate reactive oxygen-containing molecules, such as hydrogen peroxide (H2O2). These reactive oxygen molecules damage enzymes and DNA and may even cause cell death. In response, Bacillus subtilis produces at least nine potential peroxide-scavenging enzymes, two of which appear to be the primary enzymes responsible for detoxifying peroxides during vegetative growth: a catalase (encoded by katA) and an alkylhydroperoxide reductase (Ahp, encoded by ahpC). AhpC uses two redox-active cysteine residues to reduce peroxides to nontoxic molecules. A specialized thioredoxin-like protein, AhpF, is then required to restore oxidized AhpC back to its reduced state. Curiously, B. subtilis has two genes encoding Ahp: ahpC and ahpA. Although AhpC is well characterized, very little is known about AhpA. In fact, numerous bacterial species have multiple ahp genes; however, these additional Ahp proteins are generally uncharacterized. We seek to understand the role of AhpA in the bacterium's defense against toxic peroxide molecules in relation to the roles previously assigned to AhpC and catalase. Our results demonstrate that AhpA has catalytic activity similar to that of the primary enzyme, AhpC. Furthermore, our results suggest that a unique thioredoxin redox protein, AhpT, may reduce AhpA upon its oxidation by peroxides. However, unlike AhpC, which is expressed well during vegetative growth, our results suggest that AhpA is expressed primarily during postexponential growth. IMPORTANCE B. subtilis appears to produce nine enzymes designed to protect cells against peroxides; two belong to the Ahp class of peroxidases. These studies provide an initial characterization of one of these Ahp homologs and demonstrate that the two Ahp enzymes are not simply replicates of each other, suggesting that they instead are expressed at different times during growth of the cells. These results highlight the need to further study the Ahp homologs to better understand how they differ from one another and to identify their function, if any, in protection against oxidative stress. Through these studies, we may better understand why bacteria have multiple enzymes designed to scavenge peroxides and thus have a more accurate understanding of oxidative stress resistance.
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19
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Abstract
Imlay and Linn show that exposure of logarithmically growing Escherichia coli to hydrogen peroxide (H2O2) leads to two kinetically distinguishable modes of cell killing. Mode one killing is pronounced near 1 mM concentration of H2O2 and is caused by DNA damage, whereas mode-two killing requires higher concentration (>10 mM). The second mode seems to be essentially due to damage to all macromolecules. This phenomenon has also been observed in Fenton in vitro systems with DNA nicking caused by hydroxyl radical (HO•). To our knowledge, there is currently no mathematical model for predicting mode one killing in vitro or in vivo after H2O2 exposure. We propose a simple model, using Escherichia coli as a model organism and a set of ordinary differential equations. Using this model, we show that available iron and cell density, two factors potentially involved in ROS dynamics, play a major role in the prediction of the experimental results obtained by our team and in previous studies. Indeed the presence of the mode one killing is strongly related to those two parameters. To our knowledge, mode-one death has not previously been explained. Imlay and Linn (Imlay and Linn, 1986) suggested that perhaps the amount of the toxic species was reduced at high concentrations of H2O2 because hydroxyl (or other) radicals might be quenched directly by hydrogen peroxide with the concomitant formation of superoxide anion (a less toxic species). We demonstrate (mathematically and numerically) that free available iron decrease is necessary to explain mode one killing which cannot appear without it and that H2O2 quenching or consumption is not responsible for mode-one death. We are able to follow ROS concentration (particularly responsible for mode one killing) after exposure to H2O2. This model therefore allows us to understand two major parameters involved in the presence or not of the first killing mode.
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Affiliation(s)
- Lionel Uhl
- Institut de Microbiologie de la Méditerranée - Université Aix-Marseille, Laboratoire de Chimie Bactérienne, CNRS UMR7283, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Audrey Gerstel
- Institut de Microbiologie de la Méditerranée - Université Aix-Marseille, Laboratoire de Chimie Bactérienne, CNRS UMR7283, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Maialène Chabalier
- Institut de Microbiologie de la Méditerranée - Université Aix-Marseille, Laboratoire de Chimie Bactérienne, CNRS UMR7283, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Sam Dukan
- Institut de Microbiologie de la Méditerranée - Université Aix-Marseille, Laboratoire de Chimie Bactérienne, CNRS UMR7283, 31 Chemin Joseph Aiguier, 13009 Marseille, France
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20
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Abstract
The ancestors of Escherichia coli and Salmonella ultimately evolved to thrive in air-saturated liquids, in which oxygen levels reach 210 μM at 37°C. However, in 1976 Brown and colleagues reported that some sensitivity persists: growth defects still become apparent when hyperoxia is imposed on cultures of E. coli. This residual vulnerability was important in that it raised the prospect that normal levels of oxygen might also injure bacteria, albeit at reduced rates that are not overtly toxic. The intent of this article is both to describe the threat that molecular oxygen poses for bacteria and to detail what we currently understand about the strategies by which E. coli and Salmonella defend themselves against it. E. coli mutants that lack either superoxide dismutases or catalases and peroxidases exhibit a variety of growth defects. These phenotypes constitute the best evidence that aerobic cells continually generate intracellular superoxide and hydrogen peroxide at potentially lethal doses. Superoxide has reduction potentials that allow it to serve in vitro as either a weak univalent reductant or a stronger univalent oxidant. The addition of micromolar hydrogen peroxide to lab media will immediately block the growth of most cells, and protracted exposure will result in the loss of viability. The need for inducible antioxidant systems seems especially obvious for enteric bacteria, which move quickly from the anaerobic gut to fully aerobic surface waters or even to ROS-perfused phagolysosomes. E. coli and Salmonella have provided two paradigmatic models of oxidative-stress responses: the SoxRS and OxyR systems.
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21
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Gasselhuber B, Carpena X, Graf MMH, Pirker KF, Nicolussi A, Sündermann A, Hofbauer S, Zamocky M, Furtmüller PG, Jakopitsch C, Oostenbrink C, Fita I, Obinger C. Eukaryotic Catalase-Peroxidase: The Role of the Trp-Tyr-Met Adduct in Protein Stability, Substrate Accessibility, and Catalysis of Hydrogen Peroxide Dismutation. Biochemistry 2015; 54:5425-38. [DOI: 10.1021/acs.biochem.5b00831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bernhard Gasselhuber
- Department
of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Xavi Carpena
- Institut de Biologia Molecular (IBMB-CSIC), Parc Cientific de Barcelona, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Michael M. H. Graf
- Department
of Material Sciences and Process Engineering, Institute for Molecular
Modeling and Simulation, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Katharina F. Pirker
- Department
of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Andrea Nicolussi
- Department
of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Axel Sündermann
- Department
of Material Sciences and Process Engineering, Institute for Molecular
Modeling and Simulation, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Stefan Hofbauer
- Department
for Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Campus Biocenter 5, A-1030 Vienna, Austria
| | - Marcel Zamocky
- Department
of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
- Institute
of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta
21, SK-84551 Bratislava, Slovakia
| | - Paul G. Furtmüller
- Department
of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Christa Jakopitsch
- Department
of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Chris Oostenbrink
- Department
of Material Sciences and Process Engineering, Institute for Molecular
Modeling and Simulation, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Ignacio Fita
- Institut de Biologia Molecular (IBMB-CSIC), Parc Cientific de Barcelona, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Christian Obinger
- Department
of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
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22
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Kudalkar SN, Njuma OJ, Li Y, Muldowney M, Fuanta NR, Goodwin DC. A role for catalase-peroxidase large loop 2 revealed by deletion mutagenesis: control of active site water and ferric enzyme reactivity. Biochemistry 2015; 54:1648-62. [PMID: 25674665 DOI: 10.1021/bi501221a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Catalase-peroxidases (KatGs), the only catalase-active members of their superfamily, all possess a 35-residue interhelical loop called large loop 2 (LL2). It is essential for catalase activity, but little is known about its contribution to KatG function. LL2 shows weak sequence conservation; however, its length is nearly identical across KatGs, and its apex invariably makes contact with the KatG-unique C-terminal domain. We used site-directed and deletion mutagenesis to interrogate the role of LL2 and its interaction with the C-terminal domain in KatG structure and catalysis. Single and double substitutions of the LL2 apex had little impact on the active site heme [by magnetic circular dichroism or electron paramagnetic resonance (EPR)] and activity (catalase or peroxidase). Conversely, deletion of a single amino acid from the LL2 apex reduced catalase activity by 80%. Deletion of two or more apex amino acids or all of LL2 diminished catalase activity by 300-fold. Peroxide-dependent but not electron donor-dependent kcat/KM values for deletion variant peroxidase activity were reduced 20-200-fold, and kon for cyanide binding diminished by 3 orders of magnitude. EPR spectra for deletion variants were all consistent with an increase in the level of pentacoordinate high-spin heme at the expense of hexacoordinate high-spin states. Together, these data suggest a shift in the distribution of active site waters, altering the reactivity of the ferric state, toward, among other things, compound I formation. These results identify the importance of LL2 length conservation for maintaining an intersubunit interaction that is essential for an active site water distribution that facilitates KatG catalytic activity.
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Affiliation(s)
- Shalley N Kudalkar
- Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849-5312, United States
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23
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Dwyer DJ, Belenky PA, Yang JH, MacDonald IC, Martell JD, Takahashi N, Chan CT, Lobritz MA, Braff D, Schwarz EG, Ye JD, Pati M, Vercruysse M, Ralifo PS, Allison KR, Khalil AS, Ting AY, Walker GC, Collins JJ. Antibiotics induce redox-related physiological alterations as part of their lethality. Proc Natl Acad Sci U S A 2014; 111:E2100-9. [PMID: 24803433 DOI: 10.1073/pnas.1401876111] [Citation(s) in RCA: 565] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Deeper understanding of antibiotic-induced physiological responses is critical to identifying means for enhancing our current antibiotic arsenal. Bactericidal antibiotics with diverse targets have been hypothesized to kill bacteria, in part by inducing production of damaging reactive species. This notion has been supported by many groups but has been challenged recently. Here we robustly test the hypothesis using biochemical, enzymatic, and biophysical assays along with genetic and phenotypic experiments. We first used a novel intracellular H2O2 sensor, together with a chemically diverse panel of fluorescent dyes sensitive to an array of reactive species to demonstrate that antibiotics broadly induce redox stress. Subsequent gene-expression analyses reveal that complex antibiotic-induced oxidative stress responses are distinct from canonical responses generated by supraphysiological levels of H2O2. We next developed a method to quantify cellular respiration dynamically and found that bactericidal antibiotics elevate oxygen consumption, indicating significant alterations to bacterial redox physiology. We further show that overexpression of catalase or DNA mismatch repair enzyme, MutS, and antioxidant pretreatment limit antibiotic lethality, indicating that reactive oxygen species causatively contribute to antibiotic killing. Critically, the killing efficacy of antibiotics was diminished under strict anaerobic conditions but could be enhanced by exposure to molecular oxygen or by the addition of alternative electron acceptors, indicating that environmental factors play a role in killing cells physiologically primed for death. This work provides direct evidence that, downstream of their target-specific interactions, bactericidal antibiotics induce complex redox alterations that contribute to cellular damage and death, thus supporting an evolving, expanded model of antibiotic lethality.
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Njuma OJ, Ndontsa EN, Goodwin DC. Catalase in peroxidase clothing: Interdependent cooperation of two cofactors in the catalytic versatility of KatG. Arch Biochem Biophys 2013; 544:27-39. [PMID: 24280274 DOI: 10.1016/j.abb.2013.11.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 11/11/2013] [Accepted: 11/15/2013] [Indexed: 11/26/2022]
Abstract
Catalase-peroxidase (KatG) is found in eubacteria, archaea, and lower eukaryotae. The enzyme from Mycobacterium tuberculosis has received the greatest attention because of its role in activation of the antitubercular pro-drug isoniazid, and the high frequency with which drug resistance stems from mutations to the katG gene. Generally, the catalase activity of KatGs is striking. It rivals that of typical catalases, enzymes with which KatGs share no structural similarity. Instead, catalatic turnover is accomplished with an active site that bears a strong resemblance to a typical peroxidase (e.g., cytochrome c peroxidase). Yet, KatG is the only member of its superfamily with such capability. It does so using two mutually dependent cofactors: a heme and an entirely unique Met-Tyr-Trp (MYW) covalent adduct. Heme is required to generate the MYW cofactor. The MYW cofactor allows KatG to leverage heme intermediates toward a unique mechanism for H2O2 oxidation. This review evaluates the range of intermediates identified and their connection to the diverse catalytic processes KatG facilitates, including mechanisms of isoniazid activation.
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Affiliation(s)
- Olive J Njuma
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA
| | - Elizabeth N Ndontsa
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA
| | - Douglas C Goodwin
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
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25
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Cui H, Wang Y, Wang Y, Qin S. Genome-wide analysis of putative peroxiredoxin in unicellular and filamentous cyanobacteria. BMC Evol Biol 2012; 12:220. [PMID: 23157370 PMCID: PMC3514251 DOI: 10.1186/1471-2148-12-220] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Accepted: 10/25/2012] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Cyanobacteria are photoautotrophic prokaryotes with wide variations in genome sizes and ecological habitats. Peroxiredoxin (PRX) is an important protein that plays essential roles in protecting own cells against reactive oxygen species (ROS). PRXs have been identified from mammals, fungi and higher plants. However, knowledge on cyanobacterial PRXs still remains obscure. With the availability of 37 sequenced cyanobacterial genomes, we performed a comprehensive comparative analysis of PRXs and explored their diversity, distribution, domain structure and evolution. RESULTS Overall 244 putative prx genes were identified, which were abundant in filamentous diazotrophic cyanobacteria, Acaryochloris marina MBIC 11017, and unicellular cyanobacteria inhabiting freshwater and hot-springs, while poor in all Prochlorococcus and marine Synechococcus strains. Among these putative genes, 25 open reading frames (ORFs) encoding hypothetical proteins were identified as prx gene family members and the others were already annotated as prx genes. All 244 putative PRXs were classified into five major subfamilies (1-Cys, 2-Cys, BCP, PRX5_like, and PRX-like) according to their domain structures. The catalytic motifs of the cyanobacterial PRXs were similar to those of eukaryotic PRXs and highly conserved in all but the PRX-like subfamily. Classical motif (CXXC) of thioredoxin was detected in protein sequences from the PRX-like subfamily. Phylogenetic tree constructed of catalytic domains coincided well with the domain structures of PRXs and the phylogenies based on 16s rRNA. CONCLUSIONS The distribution of genes encoding PRXs in different unicellular and filamentous cyanobacteria especially those sub-families like PRX-like or 1-Cys PRX correlate with the genome size, eco-physiology, and physiological properties of the organisms. Cyanobacterial and eukaryotic PRXs share similar conserved motifs, indicating that cyanobacteria adopt similar catalytic mechanisms as eukaryotes. All cyanobacterial PRX proteins share highly similar structures, implying that these genes may originate from a common ancestor. In this study, a general framework of the sequence-structure-function connections of the PRXs was revealed, which may facilitate functional investigations of PRXs in various organisms.
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Affiliation(s)
- Hongli Cui
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Chunhui Road, Yantai 264003, People’s Republic of China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, People’s Republic of China
| | - Yipeng Wang
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Chunhui Road, Yantai 264003, People’s Republic of China
| | - Yinchu Wang
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Chunhui Road, Yantai 264003, People’s Republic of China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, People’s Republic of China
| | - Song Qin
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Chunhui Road, Yantai 264003, People’s Republic of China
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Ndontsa EN, Moore RL, Goodwin DC. Stimulation of KatG catalase activity by peroxidatic electron donors. Arch Biochem Biophys 2012; 525:215-22. [DOI: 10.1016/j.abb.2012.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 05/25/2012] [Accepted: 06/05/2012] [Indexed: 10/28/2022]
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27
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Zhao X, Khajo A, Jarrett S, Suarez J, Levitsky Y, Burger RM, Jarzecki AA, Magliozzo RS. Specific function of the Met-Tyr-Trp adduct radical and residues Arg-418 and Asp-137 in the atypical catalase reaction of catalase-peroxidase KatG. J Biol Chem 2012; 287:37057-65. [PMID: 22918833 DOI: 10.1074/jbc.m112.401208] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Catalase activity of the dual-function heme enzyme catalase-peroxidase (KatG) depends on several structural elements, including a unique adduct formed from covalently linked side chains of three conserved amino acids (Met-255, Tyr-229, and Trp-107, Mycobacterium tuberculosis KatG numbering) (MYW). Mutagenesis, electron paramagnetic resonance, and optical stopped-flow experiments, along with calculations using density functional theory (DFT) methods revealed the basis of the requirement for a radical on the MYW-adduct, for oxyferrous heme, and for conserved residues Arg-418 and Asp-137 in the rapid catalase reaction. The participation of an oxyferrous heme intermediate (dioxyheme) throughout the pH range of catalase activity is suggested from our finding that carbon monoxide inhibits the activity at both acidic and alkaline pH. In the presence of H(2)O(2), the MYW-adduct radical is formed normally in KatG[D137S] but this mutant is defective in forming dioxyheme and lacks catalase activity. KatG[R418L] is also catalase deficient but exhibits normal formation of the adduct radical and dioxyheme. Both mutants exhibit a coincidence between MYW-adduct radical persistence and H(2)O(2) consumption as a function of time, and enhanced subunit oligomerization during turnover, suggesting that the two mutations disrupting catalase turnover allow increased migration of the MYW-adduct radical to protein surface residues. DFT calculations showed that an interaction between the side chain of residue Arg-418 and Tyr-229 in the MYW-adduct radical favors reaction of the radical with the adjacent dioxyheme intermediate present throughout turnover in WT KatG. Release of molecular oxygen and regeneration of resting enzyme are thereby catalyzed in the last step of a proposed catalase reaction.
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Affiliation(s)
- Xiangbo Zhao
- Department of Chemistry, Brooklyn College, Brooklyn, New York 11210, USA
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28
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Kudalkar SN, Campbell RA, Li Y, Varnado CL, Prescott C, Goodwin DC. Enhancing the peroxidatic activity of KatG by deletion mutagenesis. J Inorg Biochem 2012; 116:106-15. [PMID: 23018273 DOI: 10.1016/j.jinorgbio.2012.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 08/07/2012] [Accepted: 08/08/2012] [Indexed: 11/23/2022]
Abstract
Catalase-peroxidase (KatG) enzymes use a peroxidase active site to facilitate robust catalase activity, an ability all other members of its superfamily lack. KatG's have a Met-Tyr-Trp covalent adduct that is essential for catalatic but not peroxidatic turnover. The tyrosine (Y226 in E. coli KatG) is supplied by a large loop (LL1) that is absent from all other plant peroxidases. Elimination of Y226 from the KatG structure, either by site directed mutagenesis (i.e., Y226F KatG) or by deletion of larger portions of LL1 invariably eliminates catalase activity, but deletion variants were substantially more active as peroxidases, up to an order of magnitude. Moreover, the deletion variants were more resistant to H(2)O(2)-dependent inactivation than Y226F KatG. Stopped-flow evaluation of reactions of H(2)O(2) with Y226F KatG and the most peroxidase active deletion variant (KatG[Δ209-228]) produced highly similar rate constants for formation of compounds I and II, and about a four-fold faster formation of compound III for the deletion variant as opposed to Y226F. Conversely, single turnover experiments showed a 60-fold slower return of Y226F KatG to its ferric state in the presence of the exogenous electron donor 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) than was determined for KatG(Δ209-228). Our data suggest that the peroxidatic output of KatG cannot be optimized simply by elimination of catalase activity alone, but also requires modifications that increase electron transfer between exogenous electron donors and the heme prosthetic group.
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29
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Mishra S, Imlay J. Why do bacteria use so many enzymes to scavenge hydrogen peroxide? Arch Biochem Biophys 2012; 525:145-60. [PMID: 22609271 DOI: 10.1016/j.abb.2012.04.014] [Citation(s) in RCA: 258] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/13/2012] [Accepted: 04/14/2012] [Indexed: 12/16/2022]
Abstract
Hydrogen peroxide (H(2)O(2)) is continuously formed by the autoxidation of redox enzymes in aerobic cells, and it also enters from the environment, where it can be generated both by chemical processes and by the deliberate actions of competing organisms. Because H(2)O(2) is acutely toxic, bacteria elaborate scavenging enzymes to keep its intracellular concentration at nanomolar levels. Mutants that lack such enzymes grow poorly, suffer from high rates of mutagenesis, or even die. In order to understand how bacteria cope with oxidative stress, it is important to identify the key enzymes involved in H(2)O(2) degradation. Catalases and NADH peroxidase (Ahp) are primary scavengers in many bacteria, and their activities and physiological impacts have been unambiguously demonstrated through phenotypic analysis and through direct measurements of H(2)O(2) clearance in vivo. Yet a wide variety of additional enzymes have been proposed to serve similar roles: thiol peroxidase, bacterioferritin comigratory protein, glutathione peroxidase, cytochrome c peroxidase, and rubrerythrins. Each of these enzymes can degrade H(2)O(2) in vitro, but their contributions in vivo remain unclear. In this review we examine the genetic, genomic, regulatory, and biochemical evidence that each of these is a bonafide scavenger of H(2)O(2) in the cell. We also consider possible reasons that bacteria might require multiple enzymes to catalyze this process, including differences in substrate specificity, compartmentalization, cofactor requirements, kinetic optima, and enzyme stability. It is hoped that the resolution of these issues will lead to an understanding of stress resistance that is more accurate and perceptive.
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Affiliation(s)
- Surabhi Mishra
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
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30
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Vlasits J, Jakopitsch C, Bernroitner M, Zamocky M, Furtmüller PG, Obinger C. Mechanisms of catalase activity of heme peroxidases. Arch Biochem Biophys 2010; 500:74-81. [DOI: 10.1016/j.abb.2010.04.018] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 04/23/2010] [Accepted: 04/24/2010] [Indexed: 11/15/2022]
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Abstract
Redox regulation of stress proteins, such as molecular chaperones, guarantees an immediate response to oxidative stress conditions. This review focuses on the two major classes of redox-regulated chaperones, Hsp33 in bacteria and typical 2-Cys peroxiredoxins in eukaryotes. Both proteins employ redox-sensitive cysteines, whose oxidation status directly controls their affinity for unfolding proteins and therefore their chaperone function. We will first discuss Hsp33, whose oxidative stress-induced disulfide bond formation triggers the partial unfolding of the chaperone, which, in turn, leads to the exposure of a high-affinity binding site for unfolded proteins. This rapid mode of activation makes Hsp33 essential for protecting bacteria against severe oxidative stress conditions, such as hypochlorite (i.e., bleach) treatment, which leads to widespread protein unfolding and aggregation. We will compare Hsp33 to the highly abundant eukaryotic typical 2-Cys peroxiredoxin, whose oxidative stress-induced sulfinic acid formation turns the peroxidase into a molecular chaperone in vitro and presumably in vivo. These examples illustrate how proteins use reversible cysteine modifications to rapidly adjust to oxidative stress conditions and demonstrate that redox regulation plays a vital role in protecting organisms against reactive oxygen species-mediated cell death.
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Affiliation(s)
- Caroline Kumsta
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
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32
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Pipirou Z, Guallar V, Basran J, Metcalfe CL, Murphy EJ, Bottrill AR, Mistry SC, Raven EL. Peroxide-Dependent Formation of a Covalent Link between Trp51 and the Heme in Cytochrome c Peroxidase. Biochemistry 2009; 48:3593-9. [DOI: 10.1021/bi802210g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zoi Pipirou
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, ICREA, Life Science Department, Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona, Spain, Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, and Protein and Nucleic Acid Chemistry Laboratory, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England
| | - Victor Guallar
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, ICREA, Life Science Department, Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona, Spain, Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, and Protein and Nucleic Acid Chemistry Laboratory, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England
| | - Jaswir Basran
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, ICREA, Life Science Department, Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona, Spain, Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, and Protein and Nucleic Acid Chemistry Laboratory, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England
| | - Clive L. Metcalfe
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, ICREA, Life Science Department, Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona, Spain, Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, and Protein and Nucleic Acid Chemistry Laboratory, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England
| | - Emma J. Murphy
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, ICREA, Life Science Department, Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona, Spain, Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, and Protein and Nucleic Acid Chemistry Laboratory, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England
| | - Andrew R. Bottrill
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, ICREA, Life Science Department, Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona, Spain, Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, and Protein and Nucleic Acid Chemistry Laboratory, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England
| | - Sharad C. Mistry
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, ICREA, Life Science Department, Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona, Spain, Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, and Protein and Nucleic Acid Chemistry Laboratory, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England
| | - Emma Lloyd Raven
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, ICREA, Life Science Department, Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona, Spain, Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, and Protein and Nucleic Acid Chemistry Laboratory, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England
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Zhao X, Yu S, Ranguelova K, Suarez J, Metlitsky L, Schelvis JPM, Magliozzo RS. Role of the oxyferrous heme intermediate and distal side adduct radical in the catalase activity of Mycobacterium tuberculosis KatG revealed by the W107F mutant. J Biol Chem 2009; 284:7030-7. [PMID: 19139098 DOI: 10.1074/jbc.m808107200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Catalase-peroxidase (KatG) is essential in Mycobacterium tuberculosis for oxidative stress management and activation of the antitubercular pro-drug isoniazid. The role of a unique distal side adduct found in KatG enzymes, involving linked side chains of residues Met255, Tyr229, and Trp107 (MYW), in the unusual catalase activity of KatG is addressed here and in our companion paper (Suarez, J., Ranguelova, K., Jarzecki, A. A., Manzerova, J., Krymov, V., Zhao, X., Yu, S., Metlitsky, L., Gerfen, G. J., and Magliozzo, R. S. (2009) J. Biol. Chem. 284, in press). The KatG[W107F] mutant exhibited severely reduced catalase activity yet normal peroxidase activity, and as isolated contains more abundant 6-coordinate heme in high spin and low spin forms compared with the wild-type enzyme. Most interestingly, oxyferrous heme is also found in the purified enzyme. Oxyferrous KatG[W107F] was prepared by photolysis in air of the carbonyl enzyme or was generated using hydrogen peroxide decayed with a t1/2 of 2 days compared with 6 min for wild-type protein. The stability of oxyenyzme was modestly enhanced in KatG[Y229F] but was not affected in KatG[M255A]. Optical stopped-flow experiments showed rapid formation of Compound I in KatG[W107F] and facile formation of oxyferrous heme in the presence of micromolar hydrogen peroxide. An analysis of the relationships between catalase activity, stability of oxyferrous enzyme, and a proposed MYW adduct radical is presented. The loss of catalase function is assigned to the loss of the MYW adduct radical and structural changes that lead to greatly enhanced stability of oxyenzyme, an intermediate of the catalase cycle of native enzyme.
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Affiliation(s)
- Xiangbo Zhao
- Department of Chemistry, Brooklyn College, Brooklyn, New York 11210, USA
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Suarez J, Ranguelova K, Jarzecki AA, Manzerova J, Krymov V, Zhao X, Yu S, Metlitsky L, Gerfen GJ, Magliozzo RS. An oxyferrous heme/protein-based radical intermediate is catalytically competent in the catalase reaction of Mycobacterium tuberculosis catalase-peroxidase (KatG). J Biol Chem 2009; 284:7017-29. [PMID: 19139099 DOI: 10.1074/jbc.m808106200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A mechanism accounting for the robust catalase activity in catalase-peroxidases (KatG) presents a new challenge in heme protein enzymology. In Mycobacterium tuberculosis, KatG is the sole catalase and is also responsible for peroxidative activation of isoniazid, an anti-tuberculosis pro-drug. Here, optical stopped-flow spectrophotometry, rapid freeze-quench EPR spectroscopy both at the X-band and at the D-band, and mutagenesis are used to identify catalase reaction intermediates in M. tuberculosis KatG. In the presence of millimolar H2O2 at neutral pH, oxyferrous heme is formed within milliseconds from ferric (resting) KatG, whereas at pH 8.5, low spin ferric heme is formed. Using rapid freeze-quench EPR at X-band under both of these conditions, a narrow doublet radical signal with an 11 G principal hyperfine splitting was detected within the first milliseconds of turnover. The radical and the unique heme intermediates persist in wild-type KatG only during the time course of turnover of excess H2O2 (1000-fold or more). Mutation of Met255, Tyr229, or Trp107, which have covalently linked side chains in a unique distal side adduct (MYW) in wild-type KatG, abolishes this radical and the catalase activity. The D-band EPR spectrum of the radical exhibits a rhombic g tensor with dual gx values (2.00550 and 2.00606) and unique gy (2.00344) and gz values (2.00186) similar to but not typical of native tyrosyl radicals. Density functional theory calculations based on a model of an MYW adduct radical built from x-ray coordinates predict experimentally observed hyperfine interactions and a shift in g values away from the native tyrosyl radical. A catalytic role for an MYW adduct radical in the catalase mechanism of KatG is proposed.
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Affiliation(s)
- Javier Suarez
- Department of Chemistry, Brooklyn College, Brooklyn, New York 11210, USA
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Kitajima S. Hydrogen Peroxide-mediated Inactivation of Two Chloroplastic Peroxidases, Ascorbate Peroxidase and 2-Cys Peroxiredoxin†. Photochem Photobiol 2008; 84:1404-9. [DOI: 10.1111/j.1751-1097.2008.00452.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Abstract
Life evolved in an anaerobic world; therefore, fundamental enzymatic mechanisms and biochemical pathways were refined and integrated into metabolism in the absence of any selective pressure to avoid reactivity with oxygen. After photosystem II appeared, environmental oxygen levels rose very slowly. During this time, microorganisms acquired oxygen tolerance by jettisoning enzymes that use glycyl radicals and exposed low-potential iron-sulfur clusters, which can be directly poisoned by oxygen. They also developed mechanisms to defend themselves against superoxide (O(2)()) and hydrogen peroxide, partially reduced oxygen species that are generated as inadvertent by-products of aerobic metabolism. Contemporary organisms have inherited both the vulnerabilities and the defenses of these ancestral microbes. Current research seeks to identify these, and bacteria comprise an exceptionally accessible experimental system that has provided many of the answers. This manuscript reviews recent developments and identifies remaining puzzles.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
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Hong SK, Cha MK, Kim IH. A glutaredoxin-fused thiol peroxidase acts as an important player in hydrogen peroxide detoxification in late-phased growth of Anabaena sp. PCC7120. Arch Biochem Biophys 2008; 475:42-9. [DOI: 10.1016/j.abb.2008.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2008] [Revised: 04/04/2008] [Accepted: 04/08/2008] [Indexed: 11/29/2022]
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Singh R, Wiseman B, Deemagarn T, Jha V, Switala J, Loewen PC. Comparative study of catalase-peroxidases (KatGs). Arch Biochem Biophys 2008; 471:207-14. [DOI: 10.1016/j.abb.2007.12.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 12/14/2007] [Accepted: 12/15/2007] [Indexed: 11/25/2022]
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Abstract
Life evolved in an anaerobic world; therefore, fundamental enzymatic mechanisms and biochemical pathways were refined and integrated into metabolism in the absence of any selective pressure to avoid reactivity with oxygen. After photosystem II appeared, environmental oxygen levels rose very slowly. During this time, microorganisms acquired oxygen tolerance by jettisoning enzymes that use glycyl radicals and exposed low-potential iron-sulfur clusters, which can be directly poisoned by oxygen. They also developed mechanisms to defend themselves against superoxide (O(2)()) and hydrogen peroxide, partially reduced oxygen species that are generated as inadvertent by-products of aerobic metabolism. Contemporary organisms have inherited both the vulnerabilities and the defenses of these ancestral microbes. Current research seeks to identify these, and bacteria comprise an exceptionally accessible experimental system that has provided many of the answers. This manuscript reviews recent developments and identifies remaining puzzles.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
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Ten-i T, Kumasaka T, Higuchi W, Tanaka S, Yoshimatsu K, Fujiwara T, Sato T. Expression, purification, crystallization and preliminary X-ray analysis of the Met244Ala variant of catalase-peroxidase (KatG) from the haloarchaeon Haloarcula marismortui. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:940-3. [PMID: 18007045 PMCID: PMC2339759 DOI: 10.1107/s1744309107046489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 09/21/2007] [Indexed: 11/10/2022]
Abstract
The covalent modification of the side chains of Trp95, Tyr218 and Met244 within the active site of Haloarcula marismortui catalase-peroxidase (KatG) appears to be common to all KatGs and has been demonstrated to be particularly significant for its bifunctionality [Smulevich et al. (2006), J. Inorg. Biochem. 100, 568-585; Jakopitsch, Kolarich et al. (2003), FEBS Lett. 552, 135-140; Jakopitsch, Auer et al. (2003), J. Biol. Chem. 278, 20185-20191; Jakopitsch et al. (2004), J. Biol. Chem. 279, 46082-46095; Regelsberger et al. (2001), Biochem. Soc. Trans. 29, 99-105; Ghiladi, Knudsen et al. (2005), J. Biol. Chem. 280, 22651-22663; Ghiladi, Medzihradzky et al. (2005), Biochemistry, 44, 15093-15105]. The Met244Ala variant of the H. marismortui KatG enzyme was expressed in haloarchaeal host cells and purified to homogeneity. The variant showed a complete loss of catalase activity, whereas the peroxidase activity of this mutant was highly enhanced owing to an increase in its affinity for the peroxidatic substrate. The variant was crystallized using the hanging-drop vapour-diffusion method with ammonium sulfate and NaCl as precipitants. The reddish-brown rod-shaped crystals obtained belong to the monoclinic space group C2, with unit-cell parameters a = 315.24, b = 81.04, c = 74.77 A, beta = 99.81 degrees . A crystal frozen using lithium sulfate as the cryoprotectant diffracted to beyond 2.0 A resolution. Preliminary X-ray analysis suggests the presence of a dimer in the asymmetric unit.
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Affiliation(s)
- Tomomi Ten-i
- Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B-10 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Takashi Kumasaka
- Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B-10 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Wataru Higuchi
- Department of Biological Sciences, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Satoru Tanaka
- Department of Biological Sciences, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Katsuhiko Yoshimatsu
- Department of Biological Sciences, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Taketomo Fujiwara
- Department of Biological Sciences, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Takao Sato
- Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B-10 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
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Netto LES, de Oliveira MA, Monteiro G, Demasi APD, Cussiol JRR, Discola KF, Demasi M, Silva GM, Alves SV, Faria VG, Horta BB. Reactive cysteine in proteins: protein folding, antioxidant defense, redox signaling and more. Comp Biochem Physiol C Toxicol Pharmacol 2007; 146:180-193. [PMID: 17045551 DOI: 10.1016/j.cbpc.2006.07.014] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Revised: 07/13/2006] [Accepted: 07/31/2006] [Indexed: 01/11/2023]
Abstract
Cysteine plays structural roles in proteins and can also participate in electron transfer reactions, when some structural folds provide appropriated environments for stabilization of its sulfhydryl group in the anionic form, called thiolate (RS(-)). In contrast, sulfhydryl group of free cysteine has a relatively high pK(a) (8,5) and as a consequence is relatively inert for redox reaction in physiological conditions. Thiolate is considerable more powerful as nucleophilic agent than its protonated form, therefore, reactive cysteine are present mainly in its anionic form in proteins. In this review, we describe several processes in which reactive cysteine in proteins take part, showing a high degree of redox chemistry versatility.
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Affiliation(s)
- Luis Eduardo Soares Netto
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil.
| | - Marcos Antonio de Oliveira
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
| | - Gisele Monteiro
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
| | - Ana Paula Dias Demasi
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
| | - José Renato Rosa Cussiol
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
| | - Karen Fulan Discola
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
| | - Marilene Demasi
- Laboratório de Bioquímica e Biofísica, Instituto Butantan, São Paulo-SP, Brazil
| | - Gustavo Monteiro Silva
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
| | - Simone Vidigal Alves
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
| | - Victor Genu Faria
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
| | - Bruno Brasil Horta
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo-SP, Brazil
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Abstract
A series of myoglobin mutants, in which distal sites are modified by site-directed mutagenesis, are able to catalyze peroxidase, catalase, and P450 reactions even though their proximal histidine ligands are intact. More importantly, reactions of P450, catalase, and peroxidase substrates and compound I of myoglobin mutants can be observed spectroscopically. Thus, detailed oxidation mechanisms were examined. On the basis of these results, we suggest that the different reactivities of P450, catalase, and peroxidase are mainly caused by their active site structures, but not the axial ligand. We have also prepared compound 0 under physiological conditions by employing a mutant of cytochrome c 552. Compound 0 is not able to oxidize ascorbic acid.
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Affiliation(s)
- Yoshihito Watanabe
- Research Center for Materials Science and Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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Ranguelova K, Girotto S, Gerfen GJ, Yu S, Suarez J, Metlitsky L, Magliozzo RS. Radical sites in Mycobacterium tuberculosis KatG identified using electron paramagnetic resonance spectroscopy, the three-dimensional crystal structure, and electron transfer couplings. J Biol Chem 2007; 282:6255-64. [PMID: 17204474 PMCID: PMC1885898 DOI: 10.1074/jbc.m607309200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Catalase-peroxidase (KatG) from Mycobacterium tuberculosis, a Class I peroxidase, exhibits high catalase activity and peroxidase activity with various substrates and is responsible for activation of the commonly used antitubercular drug, isoniazid (INH). KatG readily forms amino acid-based radicals during turnover with alkyl peroxides, and this work focuses on extending the identification and characterization of radicals forming on the millisecond to second time scale. Rapid freeze-quench electron paramagnetic resonance spectroscopy (RFQ-EPR) reveals a change in the structure of the initially formed radical in the presence of INH. Heme pocket binding of the drug and knowledge that KatG[Y229F] lacks this signal provides evidence for radical formation on residue Tyr(229). High field RFQ-EPR spectroscopy confirmed a tryptophanyl radical signal, and new analyses of X-band RFQ-EPR spectra also established its presence. High field EPR spectroscopy also confirmed that the majority radical species is a tyrosyl radical. Site-directed mutagenesis, along with simulations of EPR spectra based on x-ray structural data for particular tyrosine and tryptophan residues, enabled assignments based on predicted hyperfine coupling parameters. KatG mutants W107F, Y229F, and the double mutant W107F/Y229F showed alteration in type and yield of radical species. Results are consistent with formation of a tyrosyl radical reasonably assigned to residue Tyr(229) within the first few milliseconds of turnover. This is followed by a mixture of tyrosyl and tryptophanyl radical species and finally to only a tyrosyl radical on residue Tyr(353), which lies more distant from the heme. The radical processing of enzyme lacking the Trp(107)-Tyr(229)-Met(255) adduct (found as a unique structural feature of catalase-peroxidases) is suggested to be a reasonable assignment of the phenomena.
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Affiliation(s)
- Kalina Ranguelova
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210 and The Graduate Center of the City University of New York, NY 10016, USA
| | - Stefania Girotto
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210 and The Graduate Center of the City University of New York, NY 10016, USA
| | - Gary J. Gerfen
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Shengwei Yu
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210 and The Graduate Center of the City University of New York, NY 10016, USA
| | - Javier Suarez
- Department of Biochemistry, The Graduate Center of the City University of New York, NY 10016, USA
| | - Leonid Metlitsky
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210 and The Graduate Center of the City University of New York, NY 10016, USA
| | - Richard S. Magliozzo
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210 and The Graduate Center of the City University of New York, NY 10016, USA
- Department of Biochemistry, The Graduate Center of the City University of New York, NY 10016, USA
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Kapetanaki SM, Zhao X, Yu S, Magliozzo RS, Schelvis JPM. Modification of the active site of Mycobacterium tuberculosis KatG after disruption of the Met-Tyr-Trp cross-linked adduct. J Inorg Biochem 2006; 101:422-33. [PMID: 17188362 PMCID: PMC1885897 DOI: 10.1016/j.jinorgbio.2006.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 11/01/2006] [Accepted: 11/02/2006] [Indexed: 11/30/2022]
Abstract
Mycobacterium tuberculosis catalase-peroxidase (Mtb KatG) is a bifunctional enzyme that possesses both catalase and peroxidase activities and is responsible for the activation of the antituberculosis drug isoniazid. Mtb KatG contains an unusual adduct in its distal heme-pocket that consists of the covalently linked Trp107, Tyr229, and Met255. The KatG(Y229F) mutant lacks this adduct and has decreased steady-state catalase activity and enhanced peroxidase activity. In order to test a potential structural role of the adduct that supports catalase activity, we have used resonance Raman spectroscopy to probe the local heme environment of KatG(Y229F). In comparison to wild-type KatG, resting KatG(Y229F) contains a significant amount of 6-coordinate, low-spin heme and a more planar heme. Resonance Raman spectroscopy of the ferrous-CO complex of KatG(Y229F) suggest a non-linear Fe-CO binding geometry that is less tilted than in wild-type KatG. These data provide evidence that the Met-Tyr-Trp adduct imparts structural stability to the active site of KatG that seems to be important for sustaining catalase activity.
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Affiliation(s)
- Sofia M. Kapetanaki
- Department of Chemistry, New York University, 100 Washington Square East, Room 1001, New York, NY 10003
| | - Xiangbo Zhao
- Department of Chemistry, Brooklyn College and the Graduate Center of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210-2889
| | - Shengwei Yu
- Department of Chemistry, Brooklyn College and the Graduate Center of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210-2889
| | - Richard S. Magliozzo
- Department of Chemistry, Brooklyn College and the Graduate Center of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210-2889
| | - Johannes P. M. Schelvis
- Department of Chemistry, New York University, 100 Washington Square East, Room 1001, New York, NY 10003
- *Corresponding author. Tel.: +1 212 998 3597; fax: +1 212 260 7905. E-mail address:
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Deemagarn T, Wiseman B, Carpena X, Ivancich A, Fita I, Loewen PC. Two alternative substrate paths for compound I formation and reduction in catalase-peroxidase KatG from Burkholderia pseudomallei. Proteins 2006; 66:219-28. [PMID: 17063492 DOI: 10.1002/prot.21209] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Five residues in the multifunctional catalase-peroxidase KatG of Burkholderia pesudomallei are essential for catalase, but not peroxidase, activity. Asp141 is the only one of these catalase-specific residues not related with the covalent adduct found in KatGs that when replaced with a nonacidic residue reduces catalase activity to 5% of native levels. Replacing the nearby catalytic residue Arg108 causes a reduction in catalase activity to 35% of native levels, whereas a variant with both Asp141 and Arg108 replaced exhibits near normal catalase activity (82% of native), suggesting a synergism in the roles of the two residues in support of catalase activity in the enzyme. Among the Asp141 variants, D141E is unique in retaining normal catalase activity but with modified kinetics, suggesting more favorable compound I formation and less favorable compound I reduction. The crystal structure of the D141E variant has been determined at 1.8-A resolution, revealing that the carboxylate of Glu141 is moved only slightly compared with Asp141, but retains its hydrogen bond interaction with the main chain nitrogen of Ile237. In contrast, the low temperature ferric Electron Paramagnetic Resonance spectra of the D141A, R108A, and R108A/D141A variants are consistent with modifications of the water matrix and/or the relative positioning of the distal residue side chains. Such changes explain the reduction in catalase activity in all but the double variant R108A/D141A. Two pathways of hydrogen bonded solvent lead from the entrance channel into the heme active site, one running between Asp141 and Arg108 and the second between Asp141 and the main chain atoms of residues 237-239. It is proposed that binding of substrate H(2)O(2) to Asp141 and Arg108 controls H(2)O(2) access to the heme active site, thereby modulating the catalase reaction.
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Affiliation(s)
- Taweewat Deemagarn
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
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46
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Lee J, Cao L, Ow SY, Barrios-Llerena ME, Chen W, Wood TK, Wright PC. Proteome Changes after Metabolic Engineering to Enhance Aerobic Mineralization ofcis-1,2-Dichloroethylene. J Proteome Res 2006; 5:1388-97. [PMID: 16739990 DOI: 10.1021/pr060008t] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metabolically engineered Escherichia coli has previously been used to degrade cis-1,2-dichloroethylene (cis-DCE). The strains express the six genes of an evolved toluene ortho-monooxygenase from Burkholderia cepacia G4 (TOM-Green, which formed a reactive epoxide) with either (1) gamma-glutamylcysteine synthetase (GSHI, which forms glutathione) and the glutathione S-transferase IsoILR1 from Rhodococcus AD45 (which adds glutathione to the reactive cis-DCE epoxide) or (2) with an evolved epoxide hydrolase from Agrobacterium radiobacter AD1 (EchA F108L/I219L/C248I which converts the reactive cis-DCE epoxide to a diol). Here, the impact of this metabolic engineering for bioremediation was assessed by investigating the changes in the proteome through a quantitative shotgun proteomics technique (iTRAQ) by tracking the changes due to the sequential addition of TOM-Green, IsoILR1, and GSHI and due to adding the evolved EchA versus the wild-type enzyme to TOM-Green. For the TOM-Green/EchA system, 8 proteins out of 268 identified proteins were differentially expressed in the strain expressing EchA F108L/I219L/C248I relative to wild-type EchA (e.g., EchA, protein chain elongation factor EF-Ts, 50S ribosomal subunits L7/L12/L32/L29, cysteine synthase A, glycerophosphodiester phosphodiesterase, iron superoxide dismutase). For the TOM-Green/IsoILR1/GSHI system, the expression level of 49 proteins was changed out of 364 identified proteins. The induced proteins due to the addition of TOM-Green, IsoILR1, and GSHI were involved in the oxidative defense mechanism, pyruvate metabolism, and glutathione synthesis (e.g., 30S ribosomal subunit proteins S3 and S16, 50S ribosomal subunit protein L20, alkyl hydroperoxide reductase, lactate dehydrogenase, acetate kinase, cysteine synthase A). Enzymes involved in indole synthesis, fatty acid synthesis, gluconeogenesis, and the tricarboxylic acid cycle were repressed (e.g., tryptophanase, acetyl-CoA carboxylase, phosphoenolpyruvate carboxykinase, malate dehydrogenase). Hence, the metabolic engineering that leads to enhanced aerobic degradation of 1 mM cis-DCE (2.4-4-fold more chloride ions released) and reduced toxicity from cis-DCE epoxide results in enhanced synthesis of glutathione coupled with an induced stress response as well as repression of fatty acid synthesis, gluconeogenesis, and the tricarboxylic acid cycle.
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Affiliation(s)
- Jintae Lee
- Artie McFerrin Department of Chemical Engineering and Department of Biology, 220 Jack E. Brown Building, Texas A & M University, College Station, Texas 77843-3122, USA
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Smulevich G, Jakopitsch C, Droghetti E, Obinger C. Probing the structure and bifunctionality of catalase-peroxidase (KatG). J Inorg Biochem 2006; 100:568-85. [PMID: 16516299 DOI: 10.1016/j.jinorgbio.2006.01.033] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 01/12/2006] [Accepted: 01/12/2006] [Indexed: 10/24/2022]
Abstract
Catalase-peroxidases (KatGs) exhibit peroxidase and substantial catalase activities similar to monofunctional catalases. Crystal structures of four different KatGs reveal the presence of a peroxidase-conserved proximal and distal heme pocket together with features unique to KatG. To gain insight into their structure-function properties, many variants were produced and very similar results were obtained irrespective of the origin of the KatG mutated. This review focuses mainly on the electronic absorption and resonance Raman results together with the combined analysis of pre-steady and steady-state kinetics of various mutants involving both the peroxidase-conserved and the KatG-specific residues of recombinant KatG from the cyanobacterium Synechocystis. Marked differences in the structural role of conserved amino acids and hydrogen-bond networks in KatG with respect to the other plant peroxidases were found. Typically, the catalatic but not the peroxidatic activity was very sensitive to mutations that disrupted the KatG-typical extensive hydrogen-bonding network. Moreover, the integrity of this network is crucial for the formation of distinct protein radicals formed upon incubation of KatG with peroxides in the absence of one-electron donors. The correlation between the structural architecture and the bifunctional activity is discussed and compared with data obtained for KatGs from other organisms.
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Affiliation(s)
- Giulietta Smulevich
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Florence, Italy.
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48
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Carpena X, Wiseman B, Deemagarn T, Singh R, Switala J, Ivancich A, Fita I, Loewen PC. A molecular switch and electronic circuit modulate catalase activity in catalase-peroxidases. EMBO Rep 2006; 6:1156-62. [PMID: 16211084 PMCID: PMC1369206 DOI: 10.1038/sj.embor.7400550] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 07/29/2005] [Accepted: 09/09/2005] [Indexed: 11/08/2022] Open
Abstract
The catalase reaction of catalase-peroxidases involves catalase-specific features built into a peroxidase core. An arginine, 20 A from the active-site heme, acts as a molecular switch moving between two conformations, one that activates heme oxidation and one that activates oxoferryl heme reduction by H(2)O(2), facilitating the catalatic pathway in a peroxidase. The influence of the arginine is imparted to the heme through its association with or dissociation from a tyrosinate that modulates reactivity through a Met-Tyr-Trp crosslinked adduct and a pi electron interaction of the heme with the adduct Trp.
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Affiliation(s)
- Xavier Carpena
- Department of Microbiology, University of Manitoba, Winnipeg MB R3T 2N2, Canada
| | - Ben Wiseman
- Department of Microbiology, University of Manitoba, Winnipeg MB R3T 2N2, Canada
| | - Taweewat Deemagarn
- Department of Microbiology, University of Manitoba, Winnipeg MB R3T 2N2, Canada
| | - Rahul Singh
- Department of Microbiology, University of Manitoba, Winnipeg MB R3T 2N2, Canada
| | - Jacek Switala
- Department of Microbiology, University of Manitoba, Winnipeg MB R3T 2N2, Canada
| | - Anabella Ivancich
- Service de Bioénergétique, URA 2096 CNRS, Département de Biologie Joliot-Curie, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Ignacio Fita
- Departament de Biologia Estructural (IBMB-CSIC), Parc Científic de Barcelona, Josep Samitier 1-5, 08028 Barcelona, Spain
| | - Peter C Loewen
- Department of Microbiology, University of Manitoba, Winnipeg MB R3T 2N2, Canada
- Tel: +1 204 474 8334; Fax: +1 204 474 7603; E-mail:
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49
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Ardissone S, Laurenti E, Frendo P, Ghibaudi EM, Puppo A. Single-site mutations on the catalase–peroxidase from Sinorhizobium meliloti: role of the distal Gly and the three amino acids of the putative intrinsic cofactor. J Biol Inorg Chem 2005; 10:813-26. [PMID: 16217641 DOI: 10.1007/s00775-005-0032-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Accepted: 09/12/2005] [Indexed: 10/25/2022]
Abstract
KatB is the only catalase-peroxidase identified so far in Sinorhizobium meliloti. It plays a housekeeping role, as it is expressed throughout all the growth phases of the free-living bacterium and also during symbiosis. This paper describes the functional and structural characterization of the KatB mutants Gly303Ser, Trp95Ala, Trp95Phe, Tyr217Leu, Tyr217Phe and Met243Val carried out by optical and electron spin resonance spectroscopy. The aim of this work was to investigate the involvement of these residues in the catalatic and/or peroxidatic reaction and falls in the frame of the open dispute around the factors that influence the balance between catalatic and peroxidatic activity in heme enzymes. The Gly303 residue is not conserved in any other protein of this family, whereas the Trp95, Tyr217 and Met243 residues are thought to form an intrinsic cofactor that is likely to play a role in intramolecular electron transfer. Spectroscopic investigations show that the Gly303Ser mutant is almost similar to the wild-type KatB and should not be involved in substrate binding. Mutations on Trp95, Tyr217 and Met243 clear out the catalatic activity completely, whereas the peroxidatic activity is maintained or even increased with respect to that of the wild-type enzyme. The k (cat) values obtained for these mutants suggest that Trp95 and Tyr217 form a huge delocalized system that provides a pathway for electron transfer to the heme. Conversely, Met243 is likely to be placed close to the binding site of the organic molecules and plays a crucial role in substrate docking.
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Affiliation(s)
- Silvia Ardissone
- Dipartimento di Chimica I. F. M., Università di Torino, via Pietro Giuria 7, 10125, Turin, Italy
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Mo L, Zhang W, Wang J, Weng X, Chen S, Shao L, Pang M, Chen Z. Three-dimensional model and molecular mechanism of Mycobacterium tuberculosis catalase-peroxidase (KatG) and isoniazid-resistant KatG mutants. Microb Drug Resist 2005; 10:269-79. [PMID: 15650370 PMCID: PMC2865223 DOI: 10.1089/mdr.2004.10.269] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mycobacterium tuberculosis KatG enzyme functions both as catalase for removing hydrogen peroxide (H(2)O(2)) and as peroxidase for oxidating isoniazid (INH) to active form of anti-tuberculosis drug. Although mutations in M. tuberculosis KatG confer INH resistance in tuberculous patients, structural bases for INH-resistant mutations in the KatG gene remains poorly understood. Here, three M. tuberculosis KatG mutants bearing Arg418--> Gln, Ser315 --> Thr, or Trp321 --> Gly replacement were assessed for changes in catalase-peroxidase activities and possible structure bases relevant to such changes. These three M. tuberculosis KatG mutants exhibited a marked impairment or loss of catalase-peroxidase activities. The possible structural bases for the mutant-induced loss of enzyme activities were then analyzed using a three-dimensional model of M. tuberculosis KatG protein constructed on the basis of the crystal structure of the catalase-peroxidase from Burkholderia pseudomallei. The model suggests that three M. tuberculosis KatG mutants bearing Arg418 --> Gln, Ser315 -->Thr, or Trp321--> Gly replacement affect enzyme activities by different mechanisms, although each of them impacts consequently on a heme-associated structure, the putative oxidative site. Moreover, in addition to the widely accepted substrate-binding site, M. tuberculosis KatG may bear another H(2)O(2) binding site. This H(2)O(2) binding site appears to interact with the catalytic site by a possible electron-transfer chain, a Met255-Tyr229-Trp107 triad conserved in many catalase-peroxidases. The Ser315 --> Thr mutant may have direct effect on the catalytic site by interfering with electron transfer in addition to the previously proposed mechanism of steric constraint.
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Affiliation(s)
- L. Mo
- State Key Laboratory of Genetic Engineering, Institute of Genetics, and Huashan Hospital, Fudan University, Shanghai, China 200433
| | - W. Zhang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, and Huashan Hospital, Fudan University, Shanghai, China 200433
- Harvard Medical School, Boston MA 02215, and University of Illinois, Chicago, IL 60612
| | - J. Wang
- Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - X.H. Weng
- State Key Laboratory of Genetic Engineering, Institute of Genetics, and Huashan Hospital, Fudan University, Shanghai, China 200433
| | - S. Chen
- State Key Laboratory of Genetic Engineering, Institute of Genetics, and Huashan Hospital, Fudan University, Shanghai, China 200433
| | - L.Y. Shao
- State Key Laboratory of Genetic Engineering, Institute of Genetics, and Huashan Hospital, Fudan University, Shanghai, China 200433
| | - M.Y. Pang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, and Huashan Hospital, Fudan University, Shanghai, China 200433
| | - Z.W. Chen
- Harvard Medical School, Boston MA 02215, and University of Illinois, Chicago, IL 60612
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