2g0f
From Proteopedia
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Crystal Structure of P144A mutant of E.coli CcmG protein
Overview
CcmG, also designated DsbE, functions as a periplasmic protein, thiol:disulfide oxidoreductase and is required for cytochrome c, maturation. Here we report the crystal structures of Escherichia coli CcmG, and its two mutants, P144A and the N-terminal fifty seven-residue deletion, mutant, and two additional deletion mutants were studied by circular, dichroism. Structural comparison of E. coli CcmG with its deletion mutants, reveals that the N-terminal beta-sheet is essential for maintaining the, folding topology and consequently maintaining the active-site structure of, CcmG. Pro144 and Glu145 are key residues of the fingerprint region of, CcmG. Pro144 is in cis-configuration, and it makes van der Waals, interactions with the active-site disulfide Cys80-Cys83 and forms a, C--H...O hydrogen bond with Thr82, helping stabilize the active-site, structure. Glu145 forms a salt-bridge and hydrogen-bond network with other, residues of the fingerprint region and with Arg158, further stabilizing, the active-site structure. The cis-configuration of Pro144 makes the, backbone nitrogen and oxygen of Ala143 exposed to solvent, favorable for, interacting with binding partners. The key role of cis-Pro144 is verified, by the P144A mutant, which contains trans-Ala144 and displays redox, property changes. Structural comparison of E. coli CcmG with the recently, reported structure of CcmG in complex with the N-terminal domain of DsbD, reveals that Tyr141 undergoes conformational changes upon binding DsbD. A, cis-proline located at the N-terminus of the first beta-strand of the, betabetaalpha motif of the thioredoxin-like domain is a conserved, structural feature of the thioredoxin superfamily.
About this Structure
2G0F is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structures of E. coli CcmG and its mutants reveal key roles of the N-terminal beta-sheet and the fingerprint region., Ouyang N, Gao YG, Hu HY, Xia ZX, Proteins. 2006 Dec 1;65(4):1021-31. PMID:17019698
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