PDBsum entry: 1su9

Oxidoreductase

PDB id: 1su9

Contents

Protein chains

137 a.a. *

Waters ×300

* Residue conservation analysis

PDB id:

1su9

Name:

Oxidoreductase

Title:

Reduced structure of the soluble domain of resa

Structure:

Thiol-disulfide oxidoreductase resa. Chain: a, b. Fragment: soluble domain. Engineered: yes

Source:

Bacillus subtilis. Organism_taxid: 1423. Gene: resa, bsu23150. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.

Resolution:

1.95Å R-factor: 0.181

Authors:

A.Crow,R.M.Acheson,N.E.Le Brun,A.Oubrie

Key ref:

A.Crow et al. (2004). Structural basis of Redox-coupled protein substrate selection by the cytochrome c biosynthesis protein ResA. J Biol Chem, 279, 23654-23660. PubMed id: 15047692 DOI: 10.1074/jbc.M402823200

Date:

26-Mar-04 Release date: 11-May-04

Protein chains

P35160  (RESA_BACSU) -  Thiol-disulfide oxidoreductase resA

Seq: 179 a.a.

Struc: 137 a.a.

 Gene Ontology (GO) functional annotation 

• Biological process: oxidation-reduction process (2 terms)
• Biochemical function: antioxidant activity (2 terms)

DOI no: 10.1074/jbc.M402823200

J Biol Chem 279:23654-23660 (2004)

PubMed id: 15047692

Structural basis of Redox-coupled protein substrate selection by the cytochrome c biosynthesis protein ResA.

A.Crow, R.M.Acheson, N.E.Le Brun, A.Oubrie.

ABSTRACT

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.

Selected figure(s)

Figure 3.
FIG. 3. The accepted mechanism of disulfide:dithiol exchange by thiol-disulfide oxidoreductases. Details are discussed in the text.

Figure 5.
FIG. 5. Open and closed conformations of the redox-active cleft in oxidized and reduced structures, respectively. A, closed conformation in oxidized ResA. B, open conformation in reduced ResA. C, surface representation of the oxidized form. D, surface representation of the reduced species. A and B, selected residues from the hydrophobic cluster/cavity are shown in stick representations. Residues that line the hydrophobic cavity are shown with semi-transparent spheres, whereas those that that are buried in the oxidized state are not. C and D, regions colored red represent areas of high negative electrostatic potential (-10e), whereas blue areas indicate high positive potential (+10e). Neutral regions are colored white. The position of the S atom of the nucleophilic Cys-73 is indicated by a yellow circle in the reduced structure. Electrostatic potentials of surfaces were calculated from a Poisson-Boltzmann distribution generated with GRASP (72) and rendered with PyMOL.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2004, 279, 23654-23660) copyright 2004.

Figures were selected by an automated process.