Journal of Biological Chemistry
Volume 286, Issue 17, 29 April 2011, Pages 15182-15194
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Membrane Biology
Lipids and Topological Rules of Membrane Protein Assembly: BALANCE BETWEEN LONG AND SHORT RANGE LIPID-PROTEIN INTERACTIONS*

https://doi.org/10.1074/jbc.M110.214387Get rights and content
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The N-terminal six-transmembrane domain (TM) bundle of lactose permease of Escherichia coli is uniformly inverted when assembled in membranes lacking phosphatidylethanolamine (PE). Inversion is dependent on the net charge of cytoplasmically exposed protein domains containing positive and negative residues, net charge of the membrane surface, and low hydrophobicity of TM VII acting as a molecular hinge between the two halves of lactose permease (Bogdanov, M., Xie, J., Heacock, P., and Dowhan, W. (2008) J. Cell Biol. 182, 925–935). Net neutral lipids suppress the membrane translocation potential of negatively charged amino acids, thus increasing the cytoplasmic retention potential of positively charged amino acids. Herein, TM organization of sucrose permease (CscB) and phenylalanine permease (PheP) as a function of membrane lipid composition was investigated to extend these principles to other proteins. For CscB, topological dependence on PE only becomes evident after a significant increase in the net negative charge of the cytoplasmic surface of the N-terminal TM bundle. High negative charge is required to overcome the thermodynamic block to inversion due to the high hydrophobicity of TM VII. Increasing the positive charge of the cytoplasmic surface of the N-terminal TM hairpin of PheP, which is misoriented in PE-lacking cells, favors native orientation in the absence of PE. PheP and CscB also display co-existing dual topologies dependent on changes in the charge balance between protein domains and the membrane lipids. Therefore, the topology of both permeases is dependent on PE. However, CscB topology is governed by thermodynamic balance between opposing lipid-dependent electrostatic and hydrophobic interactions.

Membrane Biogenesis
Membrane Lipids
Membrane Proteins
Phospholipid
Sugar Transport
Phosphatidylethanolamine
Protein Synthesis
Sucrose Permease
Transmembrane Domain

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*

This work was supported, in whole or in part, by National Institutes of Health Grant GM R37 20478 (to W. D.). This work was also supported by a grant from the John Dunn Research Foundation (to W. D.).

The on-line version of this article (available at http://www.jbc.org) contains supplemental Fig. S1.