3C71

Structure of a ResA variant with a DsbA-like active site motif (CPHC)

Summary for 3C71

• Entry DOI: 10.2210/pdb3c71/pdb
• Related: 1ST9 1SU9
• Descriptor: Thiol-disulfide oxidoreductase resA, 1,2-ETHANEDIOL (3 entities in total)
• Functional Keywords: thioredoxin-like fold, cytochrome c-type biogenesis, membrane, oxidoreductase, redox-active center, signal-anchor, transmembrane
• Biological source: Bacillus subtilis
• Cellular location: Cell membrane ; Single-pass type II membrane protein : P35160
• Total number of polymer chains: 1
• Total formula weight: 16013.23

Authors

Crow, A. (deposition date: 2008-02-06, release date: 2008-08-12, Last modification date: 2024-02-21)

Primary citation

Lewin, A.,Crow, A.,Hodson, C.T.,Hederstedt, L.,Le Brun, N.E.
Effects of substitutions in the CXXC active-site motif of the extracytoplasmic thioredoxin ResA.
Biochem.J., 414:81-91, 2008

PubMed Abstract: The thiol-disulfide oxidoreductase ResA from Bacillus subtilis fulfils a reductive role in cytochrome c maturation. The pK(a) values for the CEPC (one-letter code) active-site cysteine residues of ResA are unusual for thioredoxin-like proteins in that they are both high (>8) and within 0.5 unit of each other. To determine the contribution of the inter-cysteine dipeptide of ResA to its redox and acid-base properties, three variants (CPPC, CEHC and CPHC) were generated representing a stepwise conversion into the active-site sequence of the high-potential DsbA protein from Escherichia coli. The substitutions resulted in large decreases in the pK(a) values of both the active-site cysteine residues: in CPHC (DsbA-type) ResA, DeltapK(a) values of -2.5 were measured for both cysteine residues. Increases in midpoint reduction potentials were also observed, although these were comparatively small: CPHC (DsbA-type) ResA exhibited an increase of +40 mV compared with the wild-type protein. Unfolding studies revealed that, despite the observed differences in the properties of the reduced proteins, changes in stability were largely confined to the oxidized state. High-resolution structures of two of the variants (CEHC and CPHC ResA) in their reduced states were determined and are discussed in terms of the observed changes in properties. Finally, the in vivo functional properties of CEHC ResA are shown to be significantly affected compared with those of the wild-type protein.

PubMed: 18422485
DOI: 10.1042/BJ20080356

Experimental method

X-RAY DIFFRACTION (1.9 Å)