2H1A

ResA C74A Variant

Summary for 2H1A

• Entry DOI: 10.2210/pdb2h1a/pdb
• Related: 1ST9 1SU9 2H19 2H1B 2H1D 2H1G
• Descriptor: Thiol-disulfide oxidoreductase resA, 1,2-ETHANEDIOL (3 entities in total)
• Functional Keywords: resa, c74a, mutant, thioredoxin, oxidoreductase
• Biological source: Bacillus subtilis
• Cellular location: Cell membrane ; Single-pass type II membrane protein : P35160
• Total number of polymer chains: 2
• Total formula weight: 31944.26

Authors

Lewin, A.,Crow, A.,Oubrie, A.,Le Brun, N.E. (deposition date: 2006-05-16, release date: 2006-09-19, Last modification date: 2024-02-14)

Primary citation

Lewin, A.,Crow, A.,Oubrie, A.,Le Brun, N.E.
Molecular Basis for Specificity of the Extracytoplasmic Thioredoxin ResA.
J.Biol.Chem., 281:35467-35477, 2006

PubMed Abstract: ResA, an extracytoplasmic thioredoxin from Bacillus subtilis, acts in cytochrome c maturation by reducing the disulfide bond present in apocytochromes prior to covalent attachment of heme. This reaction is (and has to be) specific, as broad substrate specificity would result in unproductive shortcircuiting with the general oxidizing thioredoxin(s) present in the same compartment. Using mutational analysis and subsequent biochemical and structural characterization of active site variants, we show that reduced ResA displays unusually low reactivity at neutral pH, consistent with the observed high pKa values>8 for both active site cysteines. Residue Glu80 is shown to play a key role in controlling the acid-base properties of the active site. A model in which substrate binding dramatically enhances the reactivity of the active site cysteines is proposed to account for the specificity of the protein. Such a substratemediated activation mechanism is likely to have wide relevance for extracytoplasmic thioredoxins.

PubMed: 16971393
DOI: 10.1074/jbc.M607047200

Experimental method

X-RAY DIFFRACTION (2.4 Å)