Quantitative Analysis of SecYEG-Mediated Insertion of Transmembrane α-Helices into the Bacterial Inner Membrane

JOURNAL OF MOLECULAR BIOLOGY

卷:425

Article

Ojemalm, Karin¹  Botelho, Salome Calado¹  Studle, Chiara¹  von Heijne, Gunnar^1,2 

[1] Stockholm Univ, Dept Biochem & Biophys, Ctr Biomembrane Res, SE-10691 Stockholm, Sweden

[2] Stockholm Univ, Sci Life Lab, SE-17177 Solna, Sweden

关键词: SecYEG;    leader peptidase;    membrane protein;    transmembrane helix;   

DOI  :  10.1016/j.jmb.2013.04.025

来源: Elsevier

【 摘 要 】

Most integral membrane proteins, both in prokaryotic and eukaryotic cells, are co-translationally inserted into the membrane via Sec-type translocons: the SecYEG complex in prokaryotes and the Sec61 complex in eukaryotes. The contributions of individual amino acids to the overall free energy of membrane insertion of single transmembrane alpha-helices have been measured for Sec61-mediated insertion into the endoplasmic reticulum (ER) membrane (Nature 450:1026-1030) but have not been systematically determined for SecYEG-mediated insertion into the bacterial inner membrane. We now report such measurements, carried out in Escherichia coli. Overall, there is a good correlation between the results found for the mammalian ER and the E. coli inner membrane, but the hydrophobicity threshold for SecYEG-mediated insertion is distinctly lower than that for Sec61-mediated insertion. (c) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

Free