2b1k: Difference between revisions

Revision as of 19:44, 3 May 2008

Crystal structure of E. coli CcmG protein

OverviewOverview

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 StructureAbout this Structure

2B1K is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

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 Page seeded by OCA on Sat May 3 19:44:22 2008

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OCA

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 '''Crystal structure of E. coli CcmG protein'''
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 [[Category: Ouyang, N.]]
 [[Category: Xia, Z X.]]
-[[Category: c-terminal thioredoxin-like domain]]
+[[Category: C-terminal thioredoxin-like domain]]
-[[Category: fingerprint rigion]]
+[[Category: Fingerprint rigion]]
-[[Category: n-terminal beta-sheet]]
+[[Category: N-terminal beta-sheet]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 19:44:22 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 02:00:13 2008''