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Updated: May 11, 2026

Förster Resonance Energy Transfer Mapping: A New Methodology to Elucidate Global Structural Features
Published on: March 16, 2022
Quantitative analysis of SecYEG-mediated insertion of transmembrane α-helices into the bacterial inner membrane
Karin Ojemalm1, Salomé Calado Botelho, Chiara Stüdle
1Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-10691 Stockholm, Sweden.
Abstract:
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 α-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.
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