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Title: The structure of Tim50(164–361) suggests the mechanism by which Tim50 receives mitochondrial presequences

The Tim50 crystal structure indicates that the IMS domain of Tim50 exhibits significant structural plasticity within the putative presequence-binding groove. Mitochondrial preproteins are transported through the translocase of the outer membrane (TOM) complex. Tim50 and Tim23 then transfer preproteins with N-terminal targeting presequences through the intermembrane space (IMS) across the inner membrane. The crystal structure of the IMS domain of Tim50 [Tim50(164–361)] has previously been determined to 1.83 Å resolution. Here, the crystal structure of Tim50(164–361) at 2.67 Å resolution that was crystallized using a different condition is reported. Compared with the previously determined Tim50(164–361) structure, significant conformational changes occur within the protruding β-hairpin of Tim50 and the nearby helix A2. These findings indicate that the IMS domain of Tim50 exhibits significant structural plasticity within the putative presequence-binding groove, which may play important roles in the function of Tim50 as a receptor protein in the TIM complex that interacts with the presequence and multiple other proteins. More interestingly, the crystal packing indicates that helix A1 from the neighboring monomer docks into the putative presequence-binding groove of Tim50(164–361), which may mimic the scenario of Tim50 and the presequence complex. Tim50 may recognize and bind the presequence helix by utilizing the innermore » side of the protruding β-hairpin through hydrophobic interactions. Therefore, the protruding β-hairpin of Tim50 may play critical roles in receiving the presequence and recruiting Tim23 for subsequent protein translocations.« less
Authors:
;  [1]
  1. University of Alabama at Birmingham, Birmingham, AL 35294 (United States)
Publication Date:
OSTI Identifier:
22420141
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica. Section F, Structural Biology Communications; Journal Volume: 71; Journal Issue: Pt 9; Other Information: PMCID: PMC4555921; PMID: 26323300; PUBLISHER-ID: wa5086; PUBLISHER-ID: S2053230X15013102; OAI: oai:pubmedcentral.nih.gov:4555921; Copyright (c) Li & Sha 2015; This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPLEXES; CONFORMATIONAL CHANGES; CRYSTAL STRUCTURE; MEMBRANES; PLASTICITY; RESOLUTION