PDBsum entry 2g0f

Oxidoreductase

PDB id: 2g0f

Contents

Protein chain

149 a.a. *

Waters ×58

* Residue conservation analysis

PDB id:

2g0f

Name:

Oxidoreductase

Title:

Crystal structure of p144a mutant of e.Coli ccmg protein

Structure:

Thiol:disulfide interchange protein dsbe. Chain: a. Fragment: residues 36-184. Synonym: ccmg protein, cytochromE C biogenesis protein ccmg. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: ccmg. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.20Å R-factor: 0.186 R-free: 0.238

Authors:

N.Ouyang,Y.G.Gao,H.Y.Hu,Z.X.Xia

Key ref:

N.Ouyang et al. (2006). Crystal structures of E. coli CcmG and its mutants reveal key roles of the N-terminal beta-sheet and the fingerprint region. Proteins, 65, 1021-1031. PubMed id: 17019698 DOI: 10.1002/prot.21184

Date:

12-Feb-06 Release date: 05-Dec-06

Protein chain

P0AA86  (DSBE_ECOLI) -  Thiol:disulfide interchange protein DsbE from Escherichia coli (strain K12)

Seq: 185 a.a.

Struc: 149 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.1002/prot.21184

Proteins 65:1021-1031 (2006)

PubMed id: 17019698

Crystal structures of E. coli CcmG and its mutants reveal key roles of the N-terminal beta-sheet and the fingerprint region.

N.Ouyang, Y.G.Gao, H.Y.Hu, Z.X.Xia.

ABSTRACT

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.

Selected figure(s)

Figure 5.
Figure 5. The active-site disulfide and the cis-proline loop of CcmG-EC in comparison with those of the P144A mutant and of DsbC in the DsbC-nDsbD complex. CcmG-EC is shown in red in the left panel, P144A in green in the central panel, DsbC in pink in the right pannel (the side-chain of Y100 in green for clarity), and nDsbD in blue in the three panels. The C H O hydrogen bond and interprotein hydrogen bonds are shown as dotted lines. This diagram was prepared using the program SETOR.

Figure 6.
Figure 6. Redox equilibrium of CcmG-EC (squares) and the P144A mutant (circles) with glutathione.

The above figures are reprinted by permission from John Wiley & Sons, Inc.: Proteins (2006, 65, 1021-1031) copyright 2006.

Figures were selected by an automated process.