PDBsum entry 3a3c

Protein transport

PDB id: 3a3c

Contents

Protein chain

451 a.a. *

Ligands

GLC-GLC

Waters ×70

* Residue conservation analysis

PDB id:

3a3c

Name:

Protein transport

Title:

Crystal structure of tim40/mia40 fusing mbp, c296s and c298s mutant

Structure:

Maltose-binding periplasmic protein, linker, mitochondrial intermembrane space import and assembly protein 40. Chain: a. Synonym: mmbp, maltodextrin-binding protein, mitochondrial import inner membrane translocase tim40. Engineered: yes. Mutation: yes. Other_details: the fusion protein of mmbp (unp residues 29-392), linker (nsssvpgrgsiegrpef), mitochondrial import inner membrane

Source:

Escherichia coli (strain k12), synthetic construct, saccharomyces cerevisiae (strain atcc 204508 / s288c). Baker's yeast. Organism_taxid: 83333, 32630, 559292. Gene: mia40, tim40, ykl195w. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.50Å R-factor: 0.254 R-free: 0.316

Authors:

S.Kawano,M.Naoe,T.Momose,N.Watanabe,T.Endo

Key ref:

S.Kawano et al. (2009). Structural basis of yeast Tim40/Mia40 as an oxidative translocator in the mitochondrial intermembrane space. Proc Natl Acad Sci U S A, 106, 14403-14407. PubMed id: 19667201

Date:

11-Jun-09 Release date: 04-Aug-09

Protein chain

P0AEX9  (MALE_ECOLI) -  Maltose/maltodextrin-binding periplasmic protein from Escherichia coli (strain K12)

Seq: 396 a.a.

Struc: 451 a.a.*

Protein chain

P36046  (MIA40_YEAST) -  Mitochondrial intermembrane space import and assembly protein 40 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 403 a.a.

Struc: 451 a.a.*

* PDB and UniProt seqs differ at 268 residue positions (black crosses)

Proc Natl Acad Sci U S A 106:14403-14407 (2009)

PubMed id: 19667201

Structural basis of yeast Tim40/Mia40 as an oxidative translocator in the mitochondrial intermembrane space.

S.Kawano, K.Yamano, M.Naoé, T.Momose, K.Terao, S.Nishikawa, N.Watanabe, T.Endo.

ABSTRACT

The mitochondrial intermembrane space (IMS) contains many small cysteine-bearing proteins, and their passage across the outer membrane and subsequent folding require recognition and disulfide bond transfer by an oxidative translocator Tim40/Mia40 in the inner membrane facing the IMS. Here we determined the crystal structure of the core domain of yeast Mia40 (Mia40C4) as a fusion protein with maltose-binding protein at a resolution of 3 A. The overall structure of Mia40C4 is a fruit-dish-like shape with a hydrophobic concave region, which accommodates a linker segment of the fusion protein in a helical conformation, likely mimicking a bound substrate. Replacement of the hydrophobic residues in this region resulted in growth defects and impaired assembly of a substrate protein. The Cys296-Cys298 disulfide bond is close to the hydrophobic concave region or possible substrate-binding site, so that it can mediate disulfide bond transfer to substrate proteins. These results are consistent with the growth phenotypes of Mia40 mutant cells containing Ser replacement of the conserved cysteine residues.