2f9s
From Proteopedia
2nd Crystal Structure Of A Soluble Domain Of ResA In The Oxidised Form
Overview
The covalent attachment of heme cofactors to the apo-polypeptides via thioether bonds is unique to the maturation of c-type cytochromes. A number of thiol-disulfide oxidoreductases prepare the apocytochrome for heme insertion in system I and II cytochrome c maturation. Although most thiol-disulfide oxidoreductases are nonspecific, the less common, specific thiol-disulfide oxidoreductases may be key to directing the usage of electrons. Here we demonstrate that unlike other thiol-disulfide oxidoreductases, the protein responsible for reducing oxidized apocytochrome c in Bacillus subtilis, ResA, is specific for cytochrome c550 and utilizes alternate conformations to recognize redox partners. We report solution NMR evidence that ResA undergoes a redox-dependent conformational change between oxidation states, as well as data showing that ResA utilizes a surface cavity present only in the reduced state to recognize a peptide derived from cytochrome c550. Finally, we confirm that ResA is a specific thiol-disulfide oxidoreductase by comparing its reactivity to our mimetic peptide with its reactivity to oxidized glutathione, a nonspecific substrate. This study biochemically demonstrates the specificity of this thiol-disulfide oxidoreductase and enables us to outline a structural mechanism of regulating the usage of electrons in a thiol-disulfide oxidoreductase system.
About this Structure
2F9S is a Single protein structure of sequence from Bacillus subtilis. Full crystallographic information is available from OCA.
Reference
Mechanism of substrate specificity in Bacillus subtilis ResA, a thioredoxin-like protein involved in cytochrome c maturation., Colbert CL, Wu Q, Erbel PJ, Gardner KH, Deisenhofer J, Proc Natl Acad Sci U S A. 2006 Mar 21;103(12):4410-5. Epub 2006 Mar 13. PMID:16537372 Page seeded by OCA on Sun May 4 03:38:25 2008
