Spontaneous transmembrane helix insertion thermodynamically mimics translocon-guided insertion.

ABSTRACT: The favourable transfer free energy for a transmembrane (TM) α-helix between the aqueous phase and lipid bilayer underlies the stability of membrane proteins. However, the connection between the energetics and process of membrane protein assembly by the Sec61/SecY translocon complex in vivo is not clear. Here, we directly determine the partitioning free energies of a family of designed peptides using three independent approaches: an experimental microsomal Sec61 translocon assay, a biophysical (spectroscopic) characterization of peptide insertion into hydrated planar lipid bilayer arrays, and an unbiased atomic-detail equilibrium folding-partitioning molecular dynamics simulation. Remarkably, the measured free energies of insertion are quantitatively similar for all three approaches. The m

SUBMITTER: Ulmschneider MB 

PROVIDER: S-EPMC4161982 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature