1su9

Publication Abstract from PubMed

Post-translational maturation of cytochromes c involves the covalent attachment of heme to the Cys-Xxx-Xxx-Cys-His motif of the apo-cytochrome. For this process, the two cysteines of the motif must be in the reduced state. In bacteria, this is achieved by dedicated, membrane-bound thiol-disulfide oxidoreductases with a high reducing power, which are essential components of cytochrome c maturation systems and are also linked to cellular disulfide-bond formation machineries. Here we report high-resolution structures of oxidized and reduced states of a soluble, functional domain of one such oxidoreductase, ResA, from Bacillus subtilis. The structures elucidate the structural basis of the protein's high reducing power and reveal the largest redox-coupled conformational changes observed to date in any thioredoxin-like protein. These redox-coupled changes alter the protein surface and illustrate how the redox state of ResA predetermines to which substrate it binds. Furthermore, a polar cavity, present only in the reduced state, may confer specificity to recognize apo-cytochrome c. The described features of ResA are likely to be general for bacterial cytochrome c maturation systems.

Structural basis of Redox-coupled protein substrate selection by the cytochrome c biosynthesis protein ResA.,Crow A, Acheson RM, Le Brun NE, Oubrie A J Biol Chem. 2004 May 28;279(22):23654-60. Epub 2004 Mar 26. PMID:15047692^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.