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A structural model of the active ribosome-bound membrane protein insertase YidCA structural model of the active ribosome-bound membrane protein insertase YidC
Structural highlights
FunctionYIDC_ECOLI Inner membrane protein required for the insertion and/or proper folding and/or complex formation of integral inner membrane proteins. Involved in integration of membrane proteins that insert dependently and independently of the Sec translocase complex, as well as at least 2 lipoproteins. Its own insertion requires SRP and is Sec translocase-dependent. Essential for the integration of Sec-dependent subunit a of the F(0)ATP synthase, FtsQ and SecE proteins and for Sec-independent subunit c of the F(0)ATP synthase, M13 phage procoat and the N-terminus of leader peptidase Lep. Probably interacts directly with Sec-independent substrates. Sec-dependent protein FtsQ interacts first with SecY then subsequently with YidC. Sec-dependent LacY and MalF require YidC to acquire tertiary structure and stability, a chaperone-like function, but not for membrane insertion. Stable maltose transport copmplex formation (MalFGK(2)) also requires YidC. Partially complements a Streptococcus mutans yidC2 disruption mutant.[1] [2] [3] [4] [5] [6] [7] [8] Publication Abstract from PubMedThe integration of most membrane proteins into the cytoplasmic membrane of bacteria occurs co-translationally. The universally conserved YidC protein mediates this process either individually as a membrane protein insertase, or in concert with the SecY complex. Here, we present a structural model of YidC based on evolutionary co-variation analysis, lipid-versus-protein-exposure and molecular dynamics simulations. The model suggests a distinctive arrangement of the conserved five transmembrane domains and a helical hairpin between transmembrane segment 2 (TM2) and TM3 on the cytoplasmic membrane surface. The model was used for docking into a cryo-electron microscopy reconstruction of a translating YidC-ribosome complex carrying the YidC substrate FOc. This structure reveals how a single copy of YidC interacts with the ribosome at the ribosomal tunnel exit and identifies a site for membrane protein insertion at the YidC protein-lipid interface. Together, these data suggest a mechanism for the co-translational mode of YidC-mediated membrane protein insertion. A structural model of the active ribosome-bound membrane protein insertase YidC.,Wickles S, Singharoy A, Andreani J, Seemayer S, Bischoff L, Berninghausen O, Soeding J, Schulten K, van der Sluis EO, Beckmann R Elife (Cambridge). 2014 Jul 10:e03035. doi: 10.7554/eLife.03035. PMID:25012291[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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