PDBsum entry 2ciu

Protein transport

PDB id: 2ciu

Contents

Protein chain

123 a.a. *

Waters ×167

* Residue conservation analysis

PDB id:

2ciu

Name:

Protein transport

Title:

Structure of the ims domain of the mitochondrial import protein tim21 from s. Cerevisiae

Structure:

Import inner membrane translocase subunit tim21 mitochondrial. Chain: a. Fragment: ims domain, residues 103-225. Synonym: tim21p. Engineered: yes

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 4932. Organ: mitochondrium. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.60Å R-factor: 0.198 R-free: 0.248

Authors:

R.Albrecht,K.Zeth,P.Rehling,N.Pfanner

Key ref:

R.Albrecht et al. (2006). The Tim21 binding domain connects the preprotein translocases of both mitochondrial membranes. EMBO Rep, 7, 1233-1238. PubMed id: 17099692 DOI: 10.1038/sj.embor.7400828

Date:

24-Mar-06 Release date: 21-Dec-06

Protein chain

P53220  (TIM21_YEAST) -  Mitochondrial import inner membrane translocase subunit TIM21 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 239 a.a.

Struc: 123 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1038/sj.embor.7400828

EMBO Rep 7:1233-1238 (2006)

PubMed id: 17099692

The Tim21 binding domain connects the preprotein translocases of both mitochondrial membranes.

R.Albrecht, P.Rehling, A.Chacinska, J.Brix, S.A.Cadamuro, R.Volkmer, B.Guiard, N.Pfanner, K.Zeth.

ABSTRACT

Proteins destined for the mitochondrial matrix are imported by the translocase of the outer membrane--the TOM complex--and the presequence translocase of the inner membrane--the TIM23 complex. At present, there is no structural information on components of the presequence translocase. Tim21, a subunit of the presequence translocase consisting of a membrane anchor and a carboxy-terminal domain exposed to the intermembrane space, directly connects the TOM and TIM23 complexes by binding to the intermembrane space domain of the Tom22 receptor. We crystallized the binding domain of Tim21 of Saccharomyces cerevisiae and determined its structure at 1.6 A resolution. The Tim21 structure represents a new alpha/beta-mixed protein fold with two alpha-helices flanked by an extended eight-stranded beta-sheet. We also identified a core sequence of Tom22 that binds to Tim21. Furthermore, negatively charged amino-acid residues of Tom22 are important for binding to Tim21. Here we suggest a mechanism for the TOM-TIM interaction.

Selected figure(s)

Figure 2.
Figure 2 Crystal structure of Tim21[IMS]. (A) Views of the molecular structure of Tim21[IMS] (top) with labelled -helices (green) and -strands (red). Images were generated using Molscript (Kraulis, 1991). Surface presentations of the Tim21[IMS] molecule are shown (bottom). Positive and negative potentials are coloured blue and red, respectively. The images were generated using Grasp (Nicholls et al, 1991). (B) Schematic representation of the Tim21[IMS] fold. (C) Sequence of Tim21[IMS] and distribution of secondary structure elements. (D) Hydrogen bonds (dashed) between the helical part and the antiparallel -sheet. Tim21[IMS], translocase of the inner membrane.

Figure 3.
Figure 3 Surface presentations of Tim21[IMS]. Conserved positively charged (blue), negatively charged (red), amphipathic (green) and hydrophobic (black) residues on the surface are shown. Ten unicellular organisms were compared (Saccharomyces cerevisiae, Aspergillus fumigatus, Neurospora crassa, Candida albicans, Kluyveromyces lactis, Aphis gossypii, Candida glabrata, Desulfomusa hansenii, Yarrowia lipolytica, Schizosaccharomyces pombe). Images were generated using DINO (http://www.dino3d.org/). Tim21[IMS], translocase of the inner membrane.

The above figures are reprinted from an Open Access publication published by Macmillan Publishers Ltd: EMBO Rep (2006, 7, 1233-1238) copyright 2006.

Figures were selected by the author.