Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Structure of the SecY channel during initiation of protein translocation.
Journal, issue, pages	Nature, Vol. 506, Issue 7486, Page 102-106, Year 2014
Publish date	Feb 6, 2014
Authors	Eunyong Park / Jean-François Ménétret / James C Gumbart / Steven J Ludtke / Weikai Li / Andrew Whynot / Tom A Rapoport / Christopher W Akey /
PubMed Abstract	Many secretory proteins are targeted by signal sequences to a protein-conducting channel, formed by prokaryotic SecY or eukaryotic Sec61 complexes, and are translocated across the membrane during ...Many secretory proteins are targeted by signal sequences to a protein-conducting channel, formed by prokaryotic SecY or eukaryotic Sec61 complexes, and are translocated across the membrane during their synthesis. Crystal structures of the inactive channel show that the SecY subunit of the heterotrimeric complex consists of two halves that form an hourglass-shaped pore with a constriction in the middle of the membrane and a lateral gate that faces the lipid phase. The closed channel has an empty cytoplasmic funnel and an extracellular funnel that is filled with a small helical domain, called the plug. During initiation of translocation, a ribosome-nascent chain complex binds to the SecY (or Sec61) complex, resulting in insertion of the nascent chain. However, the mechanism of channel opening during translocation is unclear. Here we have addressed this question by determining structures of inactive and active ribosome-channel complexes with cryo-electron microscopy. Non-translating ribosome-SecY channel complexes derived from Methanocaldococcus jannaschii or Escherichia coli show the channel in its closed state, and indicate that ribosome binding per se causes only minor changes. The structure of an active E. coli ribosome-channel complex demonstrates that the nascent chain opens the channel, causing mostly rigid body movements of the amino- and carboxy-terminal halves of SecY. In this early translocation intermediate, the polypeptide inserts as a loop into the SecY channel with the hydrophobic signal sequence intercalated into the open lateral gate. The nascent chain also forms a loop on the cytoplasmic surface of SecY rather than entering the channel directly.
External links	Nature / PubMed:24153188 / PubMed Central
Methods	EM (single particle)
Resolution	9.0 - 10.1 Å
Structure data	5691 4v4n EMDB-5691: Structure of the SecY protein translocation channel in action PDB-4v4n: Structure of the Methanococcus jannaschii ribosome-SecYEBeta channel complex Method: EM (single particle) / Resolution: 9.0 Å 5692 3j45 EMDB-5692: Structure of the SecY protein translocation channel in action PDB-3j45: Structure of a non-translocating SecY protein channel with the 70S ribosome Method: EM (single particle) / Resolution: 9.5 Å 5693 3j46 EMDB-5693, PDB-3j46: Structure of the SecY protein translocation channel in action Method: EM (single particle) / Resolution: 10.1 Å
Source	Methanocaldococcus jannaschii (archaea) escherichia coli (E. coli) methanococcus jannaschii (archaea)
Keywords	RIBOSOME/PROTEIN TRANSPORT / 70S / SECYEG / protein translocation channel / RIBOSOME-PROTEIN TRANSPORT complex / preprotein translocase / nascent chain / archaea / archaeal / ribosomal / 50S / protein synthesis / RNA / large subunit / co-translational translocation / protein conducting channel