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Structure, Function and Diversity in the Bacterial Cytochrome c Peroxidase Family

细菌细胞色素 c 过氧化物酶家族的结构、功能和多样性

基本信息

批准号：
9240248
负责人：
SEAN J ELLIOTT
金额：
$ 32.41万
依托单位：
BOSTON UNIVERSITY (CHARLES RIVER CAMPUS)
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-01-01 至 2020-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9240248
关键词：
Active Sites Address Adopted Aerobic Amino Acid Sequence Bacteria Base Sequence Binding Biochemistry Bioinformatics Burkholderia Campylobacter jejuni Cell Respiration Characteristics Chemistry Citrobacter Complex Core Protein Coupling Cytochrome c Group Cytochrome c Peroxidase Detection Development Drug Metabolic Detoxication Electrochemistry Electron Spin Resonance Spectroscopy Electron Transport Electrons Elements Enzymatic Biochemistry Enzymes Escherichia coli Evaluation Family Family member Freezing Generations Genome Goals Gram-Negative Bacteria Health Heme Human Hydrogen Peroxide Iron Link Lung Maps Modeling Molecular Molecular Conformation Mossbauer Spectroscopy Mutate N-terminal Names Nature Operon Optics Organism Orthologous Gene Oxidation-Reduction Oxides Paint Pathogenicity Peroxidases Peroxides Physiological Portraits Post-Translational Protein Processing Process Property Protein Precursors Proteins Pseudomonas aeruginosa Quinones Reaction Regulation Salmonella Side Site Spectrum Analysis Structure Structure-Activity Relationship Tyrosine United States National Institutes of Health Ursidae Family Variant Vertebral column Vibrio Water X-Ray Crystallography Yersinia pestis antimicrobial base cofactor cytochrome c drug discovery drug synthesis enteric pathogen gene product heme a in vivo insight member methylamine dehydrogenase microbial microorganism novel oxidation paralogous gene pathogen periplasm protein folding trait

项目摘要

PROJECT SUMMARY Hydrogen peroxide is hazardous, though common side-productive of aerobic respiration; and many gram negative bacteria synthesize cytochrome c peroxidase (bCCP) enzymes to detoxify the peroxide by reducing it to water. bCCPs are a large family of enzymes that are marked by (at least two) c-type heme cofactors that are covalently attached into the protein backbone by the action of the cytochrome c maturation machinery. bCCPs encompass “true” bCCP enzymes that engage primarily in the chemistry implied by their name, but also other enzymes such as MauG, which is responsible for the oxidative coupling of two tyrosine side-chains in the methylamine dehydrogenase precursor (pre-MADH) to make functional MADH, that bears a unique tryptophanyl tryptophane quinone (TTQ) cofactor. The structural bases for the differences of fundamental chemistry displayed by bCCP and MauG are poorly understood to date, but are certainly linked to the differences in the redox chemistry of conserved heme cofactors. In true bCCP enzymes, peroxidatic heme (FeL) is reponsible for peroxide binding and reduction; while electrons are transmitted to the active site via a heme that is over 500 mV higher in potential (FeH). In MauG, the potentials of the two heme cofactors are quite close, though how this trait is linked to reactivity is enigmatic. This proposal will elucidate the structure-function relationships of the bCCP family, including the distinctive chemistry of MauG vs. bCCP, and the molecular determinants for activation found within the bCCP family. Further, we have employed bioinformatics approaches to reveal new branches of the bCCP family; these include enzymes like YhjA found in enteric pathogens such as E. coli. YhjA and its paralogs possess a third, N-terminal heme binding domain, with an unknown function. A second new class of enzymes displays sequence-based traits that make it appear to be a MauG paralog, but they are found predominantly in the lung pathogen Burkholderia and not in a mau operon. Here will determine the chemistry of these novel bCCP in order to better understand the range of chemistry of the entire family. The objectives of this proposal are to reveal the stucture-function relationship amongst the members of the bCCP family, and to develop new models for the novel chemistries of enzymes such as Yhja, and the previously unreported Burkholderia bCCPs. To do so, a combination of enzymology, protein electrochemistry, and various spectroscopies (EPR, Mössbauer) and x-ray crystallography will be used to paint a portrait of the reactivities and conformational dynamics displayed by the diverse bCCP family members. As bCCP is an enzyme that is on the front-line of the native defenses of NIH Select List pathogens incuding Pseudomonas aeruginosa, Burkholderia complex speices, Vibrio cholarae, Campylobacter jejuni, Escherichia coli, Citrobacter, and Yersinia pestis, these studies will provide fundamental insight into the long-term development of new antimicrobial compounds that will target the novel features of bCCP structure.

项目总结