The Active-Site Cysteinyls and Hydrophobic Cavity Residues of ResA Are Important for Cytochrome c Maturation in Bacillus subtilis
| Autor: | Lars Hederstedt, Nick E. Le Brun, Christopher T. C. Hodson, Allison Lewin |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Cytochrome
Recombinant Fusion Proteins Molecular Sequence Data Bacillus subtilis Microbiology Protein Structure Secondary Protein structure Bacterial Proteins parasitic diseases Cytochrome c oxidase Amino Acid Sequence Molecular Biology Binding Sites Sequence Homology Amino Acid biology Cytochrome b Cytochrome c Cytochromes c Active site biology.organism_classification Enzymes and Proteins Transmembrane domain Biochemistry Mutagenesis Site-Directed biology.protein Hydrophobic and Hydrophilic Interactions |
| Zdroj: | Journal of Bacteriology. 190:4697-4705 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.00145-08 |
| Popis: | ResA is an extracytoplasmic membrane-bound thiol-disulfide oxidoreductase required for cytochrome c maturation in Bacillus subtilis . Previous biochemical and structural studies have revealed that the active-site cysteinyls cycle between oxidized and reduced states with a low reduction potential and that, upon reduction, a hydrophobic cavity forms close to the active site. Here we report in vivo studies of ResA-deficient B. subtilis complemented with a series of ResA variants. Using a range of methods to analyze the cellular cytochrome c content, we demonstrated (i) that the N-terminal transmembrane segment of ResA serves principally to anchor the protein to the cytoplasmic membrane but also plays a role in mediating the activity of the protein; (ii) that the active-site cysteines are important for cytochrome c maturation activity; (iii) that Pro141, which forms part of the hydrophobic cavity and which adopts a cis conformation, plays an important role in protein stability; (iv) that Glu80, which lies at the base of the hydrophobic cavity, is important for cytochrome c maturation activity; and, finally, (v) that Pro141 and Glu80 ResA mutant variants promote selective maturation of low levels of one c -type cytochrome, subunit II of the cytochrome c oxidase caa 3 , indicating that this apocytochrome is distinct from the other three endogenous c -type cytochromes of B. subtilis . |
| Databáze: | OpenAIRE |
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