6zzz | pdb_00006zzz

Crystal structure of yeast Sec62 cytoplasmic domain

spinqualitylabelsall models 6zzz, resolution 2.54Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6zzz is a 2 chain structure with sequence from Baker's yeast. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, MES, SO4 NonStd Res: MSE Gene: SEC62, YPL094C, LPG14C (Baker's yeast) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SEC62_YEAST] Acts as component of the Sec62/63 complex which is involved in SRP-independent post-translational translocation across the endoplasmic reticulum (ER) and functions together with the Sec61 complex and KAR2 in a channel-forming translocon complex. In an initial step, the signal sequence seems to bind simultaneously to SEC61 and SEC62. SEC62 and SEC63 are required for interactions between SEC61 and translocating polypeptides. SEC62 may affect SEC1-polypeptide interactions by increasing the affinity of targeting pathways for SEC61 and/or by modifying SEC61 to allow more efficient polypeptide interaction. A cycle of assembly and disassembly of Sec62/63 complex from SEC61 may govern the activity of the translocon. SEC62 is essential for cell growth. Publication Abstract from PubMed In eukaryotes, most secretory and membrane proteins are targeted by an N-terminal signal sequence to the endoplasmic reticulum, where the trimeric Sec61 complex serves as protein-conducting channel (PCC). In the post-translational mode, fully synthesized proteins are recognized by a specialized channel additionally containing the Sec62, Sec63, Sec71, and Sec72 subunits. Recent structures of this Sec complex in the idle state revealed the overall architecture in a pre-opened state. Here, we present a cryo-EM structure of the yeast Sec complex bound to a substrate, and a crystal structure of the Sec62 cytosolic domain. The signal sequence is inserted into the lateral gate of Sec61alpha similar to previous structures, yet, with the gate adopting an even more open conformation. The signal sequence is flanked by two Sec62 transmembrane helices, the cytoplasmic N-terminal domain of Sec62 is more rigidly positioned, and the plug domain is relocated. We crystallized the Sec62 domain and mapped its interaction with the C-terminus of Sec63. Together, we obtained a near-complete and integrated model of the active Sec complex. Architecture of the active post-translational Sec translocon.,Weng TH, Steinchen W, Beatrix B, Berninghausen O, Becker T, Bange G, Cheng J, Beckmann R EMBO J. 2020 Dec 11:e105643. doi: 10.15252/embj.2020105643. PMID:33305433 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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