2h1a
From Proteopedia
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ResA C74A Variant
Overview
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.
About this Structure
2H1A is a Single protein structure of sequence from Bacillus subtilis with as ligand. Full crystallographic information is available from OCA.
Reference
Molecular basis for specificity of the extracytoplasmic thioredoxin ResA., Lewin A, Crow A, Oubrie A, Le Brun NE, J Biol Chem. 2006 Nov 17;281(46):35467-77. Epub 2006 Sep 13. PMID:16971393
Page seeded by OCA on Thu Feb 21 17:37:10 2008
Categories: Bacillus subtilis | Single protein | Brun, N E.Le. | Crow, A. | Lewin, A. | Oubrie, A. | EDO | C74a | Mutant | Resa | Thioredoxin | Variant
