PMID:11843181
| Citation |
Li, Q, Hu, HY, Wang, WQ and Xu, GJ (2001) Structural and redox properties of the leaderless DsbE (CcmG) protein: both active-site cysteines of the reduced form are involved in its function in the Escherichia coli periplasm. Biol. Chem. 382:1679-86 |
|---|---|
| Abstract |
The thiol/disulfide oxidoreductases play important roles in ensuring the correct formation of disulfide bonds, of which the DsbE protein, also called CcmG, is the one implicated in electron transfer for cytochrome c maturation in the periplasm of Escherichia coli. The soluble, N-terminally truncated DsbE was overexpressed and purified to homogeneity. Here we report the structural and redox properties of the leaderless form (DsbEL-). During the redox reaction, the protein undergoes a structural transformation resulting in a more stable reduced form, but this form shows very low reactivity in thiol/ disulfide exchange of cysteine residues and low activity in accelerating the reduction of insulin. The standard redox potential (E'0) for the active thiol/ disulfide was determined to be -0.186 V; only one of the two cysteines (Cys80) was suggested to be the active residue in the redox reaction. From the aspect of biochemical properties, DsbE can be regarded as a weak reductant in the Escherichia coli periplasm. This implies that the function of DsbE in cytochrome c maturation can be ascribed to its active-site cysteines and the structure of the reduced form. |
| Links |
PubMed Online version:10.1515/BC.2001.203 |
| Keywords |
Binding Sites; Circular Dichroism; Cysteine/metabolism; Electrophoresis, Polyacrylamide Gel; Escherichia coli/metabolism; Molecular Weight; Oxidation-Reduction; Oxidoreductases/metabolism; Periplasm/metabolism; Periplasmic Proteins; Protein Folding; Spectrometry, Fluorescence |
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