3j45

From Proteopedia

Revision as of 05:44, 6 November 2013

Template:STRUCTURE 3j45

Structure of a non-translocating SecY protein channel with the 70S ribosome

Template:ABSTRACT PUBMED 24153188

Function

[RL29_ECOLI] Binds 23S rRNA. It is not essential for growth.[HAMAP-Rule:MF_00374] One of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit. Contacts trigger factor (PubMed:12226666).[HAMAP-Rule:MF_00374] [SECG_ECOLI] Subunit of the protein translocation channel SecYEG. Overexpression of some hybrid proteins has been thought to jam the protein secretion apparatus resulting in cell death; while this may be true it also results in FtsH-mediated degradation of SecY. Treatment with antibiotics that block translation elongation such as chloramphenicol also leads to degradation of SecY and SecE but not SecG. [SECE_ECOLI] Essential subunit of the protein translocation channel SecYEG. Clamps together the 2 halves of SecY. May contact the channel plug during translocation. Overexpression of some hybrid proteins has been thought to jam the protein secretion apparatus resulting in cell death; while this may be true it also results in FtsH-mediated degradation of SecY.^[1] [SECY_ECOLI] The central subunit of the protein translocation channel SecYEG. Consists of two halves formed by TMs 1-5 and 6-10. These two domains form a lateral gate at the front which open onto the bilayer between TMs 2 and 7, and are clamped together by SecE at the back. The channel is closed by both a pore ring composed of hydrophobic SecY resides and a short helix (helix 2A) on the extracellular side of the membrane which forms a plug. The plug probably moves laterally to allow the channel to open. The ring and the pore may move independently. SecY is required to insert newly synthesized SecY into the inner membrane. Overexpression of some hybrid proteins has been thought to jam the protein secretion apparatus resulting in cell death; while this may be true, overexpression also results in FtsH-mediated degradation of SecY.[HAMAP-Rule:MF_01465] [RL23_ECOLI] One of the early assembly proteins, it binds 23S rRNA; is essential for growth. One of the proteins that surround the polypeptide exit tunnel on the outside of the subunit. Acts as the docking site for trigger factor (PubMed:12226666) for Ffh binding to the ribosome (SRP54, PubMed:12756233 and PubMed:12702815) and to nascent polypeptide chains (PubMed:12756233).[HAMAP-Rule:MF_01369] [RL24_ECOLI] One of two assembly initiator proteins, it binds directly to the 5'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit. It is not thought to be involved in the functions of the mature 50S subunit in vitro.^[2] One of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit.^[3]

About this Structure

3j45 is a 11 chain structure with sequence from Cortinarius roseobulbus, Escherichia coli and Gekko coi. Full crystallographic information is available from OCA.

Reference

• Park E, Menetret JF, Gumbart JC, Ludtke SJ, Li W, Whynot A, Rapoport TA, Akey CW. Structure of the SecY channel during initiation of protein translocation. Nature. 2013 Oct 23. doi: 10.1038/nature12720. PMID:24153188 doi:http://dx.doi.org/10.1038/nature12720

1. ↑ Froderberg L, Houben EN, Baars L, Luirink J, de Gier JW. Targeting and translocation of two lipoproteins in Escherichia coli via the SRP/Sec/YidC pathway. J Biol Chem. 2004 Jul 23;279(30):31026-32. Epub 2004 May 12. PMID:15140892 doi:10.1074/jbc.M403229200
2. ↑ Spillmann S, Nierhaus KH. The ribosomal protein L24 of Escherichia coli is an assembly protein. J Biol Chem. 1978 Oct 10;253(19):7047-50. PMID:357435
3. ↑ Spillmann S, Nierhaus KH. The ribosomal protein L24 of Escherichia coli is an assembly protein. J Biol Chem. 1978 Oct 10;253(19):7047-50. PMID:357435