PDBsum entry 1u3a

Oxidoreductase

PDB id: 1u3a

Contents

Protein chains

187 a.a. *

Ligands

PE5 ×2

Waters ×259

* Residue conservation analysis

PDB id:

1u3a

Name:

Oxidoreductase

Title:

Mutant dsba

Structure:

Thiol: disulfide interchange protein dsba. Chain: a, b, d, e. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: dsba. Ppfa, dsf. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PQS)

Resolution:

2.00Å R-factor: 0.216 R-free: 0.272

Authors:

L.Serre

Key ref:

E.Ondo-Mbele et al. (2005). Intriguing conformation changes associated with the trans/cis isomerization of a prolyl residue in the active site of the DsbA C33A mutant. J Mol Biol, 347, 555-563. PubMed id: 15755450 DOI: 10.1016/j.jmb.2005.01.049

Date:

21-Jul-04 Release date: 03-May-05

Protein chains

P0AEG4  (DSBA_ECOLI) -  Thiol:disulfide interchange protein DsbA from Escherichia coli (strain K12)

Seq: 208 a.a.

Struc: 187 a.a.*

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

DOI no: 10.1016/j.jmb.2005.01.049

J Mol Biol 347:555-563 (2005)

PubMed id: 15755450

Intriguing conformation changes associated with the trans/cis isomerization of a prolyl residue in the active site of the DsbA C33A mutant.

E.Ondo-Mbele, C.Vivès, A.Koné, L.Serre.

ABSTRACT

Escherichia coli DsbA belongs to the thioredoxin family and catalyzes the formation of disulfide bonds during the folding of proteins in the bacterial periplasm. It active site (C30-P31-H32-C33) consists of a disulfide bridge that is transferred to newly translocated proteins. The work reported here refers to the DsbA mutant termed C33A that retains, towards reduced unfolded thrombin inhibitor, an activity comparable with the wild-type enzyme. Besides, C33A is also able to form a stable covalent complex with DsbB, the membrane protein responsible for maintaining DsbA in its active form. We have determined the crystal structure of C33A at 2.0 angstroms resolution. Although the general architecture of wt DsbA is conserved, we observe the trans/cis isomerization of P31 in the active site and further conformational changes in the so-called "peptide binding groove" region. Interestingly, these modifications involve residues that are specific to DsbA but not to the thioredoxin family fold. The C33A crystal structure exhibits as well a hydrophobic ligand bound close to the active site of the enzyme. The structural analysis of C33A may actually explain the peculiar behavior of this mutant in regards with its interaction with DsbB and thus provides new insights for understanding the catalytic cycle of DsbA.

Selected figure(s)

Figure 1.
Figure 1. Ribbon representation of the C33A dimers. C30 and A33 are represented by green ball-and-stick. (a) (Form Ia) crystal structure containing dodecyl-maltoside (DDM) (in magenta ball-and-stick). (b) (Form II) crystal structure containing PEG (in magenta ball-and-stick). All Figures have been generated with Molscript26 and Pymol (DeLano. http://www.pymol.org).

Figure 4.
Figure 4. Structural rearrangement of V39, F36 and F93 around the ligand. DDM (green) or PEG (magenta) overlap with F36 residue in the wt enzyme structures (reduced and oxidized in gray). The same residues in C33A are painted in yellow.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2005, 347, 555-563) copyright 2005.

Figures were selected by an automated process.