Weak pulling forces exerted on Nin-orientated transmembrane segments during co-translational insertion into the inner membrane of Escherichia coli

Florian Cymer; Nurzian Ismail; Gunnar von Heijne

doi:10.1016/j.febslet.2014.03.050

Weak pulling forces exerted on Nin-orientated transmembrane segments during co-translational insertion into the inner membrane of Escherichia coli

FEBS Lett. 2014 May 21;588(10):1930-4. doi: 10.1016/j.febslet.2014.03.050. Epub 2014 Apr 12.

Authors

Florian Cymer¹, Nurzian Ismail¹, Gunnar von Heijne²

Affiliations

¹ Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
² Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden; Science for Life Laboratory, Stockholm University, Box 1031, SE-171 21 Solna, Sweden. Electronic address: gunnar@dbb.su.se.

PMID: 24726730
DOI: 10.1016/j.febslet.2014.03.050

Abstract

Transmembrane helices (TMHs) in membrane proteins can be orientated with their N-terminus towards the cytoplasm (Nin), or facing the non-cytoplasmic side (Nout). Most membrane proteins are inserted co-translationally into membranes, aided by Sec-type translocons. Since the final orientation of Nin- and Nout-orientated TMHs differs, they could also interact differently with the translocon and the surrounding membrane during insertion. We measured pulling forces exerted on Nin-orientated TMHs during co-translational insertion into the inner membrane of Escherichia coli. Our results demonstrate that Nin-orientated TMHs experience a weaker pulling force but retain the overall biphasic force profile seen previously for Nout-orientated TMHs (Ismail et al., 2012 [1]).

Keywords: Membrane insertion; Transmembrane helix; Type 2 membrane protein.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Base Sequence
Cell Membrane / metabolism*
Electrophoresis, Polyacrylamide Gel
Escherichia coli / genetics
Escherichia coli / metabolism*
Escherichia coli Proteins / chemistry
Escherichia coli Proteins / genetics
Escherichia coli Proteins / metabolism*
Hydrophobic and Hydrophilic Interactions
Membrane Proteins / chemistry
Membrane Proteins / genetics
Membrane Proteins / metabolism*
Models, Biological
Mutation
Protein Biosynthesis
Protein Structure, Secondary
Protein Transport
Sequence Homology, Nucleic Acid

Substances

Escherichia coli Proteins
Membrane Proteins