Sensitivity of single membrane-spanning alpha-helical peptides to hydrophobic mismatch with a lipid bilayer: Effects on backbone structure, orientation, and extent of membrane incorporation


de Planque, M.R.R., Goormaghtigh, E., Greathouse, D.V., Koeppe II, R.E., Kruijtzer, J.A.W., Liskamp, R.M.J., de Kruijff, B. and Killian, J.A. (2001) Sensitivity of single membrane-spanning alpha-helical peptides to hydrophobic mismatch with a lipid bilayer: Effects on backbone structure, orientation, and extent of membrane incorporation Biochemistry, 40, (16), pp. 5000-5010. (doi:10.1021/bi000804r).

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Description/Abstract

The extent of matching of membrane hydrophobic thickness with the hydrophobic length of transmembrane protein segments potentially constitutes a major director of membrane organization. Therefore, the extent of mismatch that can be compensated, and the types of membrane rearrangements that result, can provide valuable insight into membrane functionality. In the present study, a large family of synthetic peptides and lipids is used to investigate a range of mismatch situations. Peptide conformation, orientation, and extent of incorporation are assessed by infrared spectroscopy, tryptophan fluorescence, circular dichroism, and sucrose gradient centrifugation. It is shown that peptide backbone structure is not significantly affected by mismatch, even when the extent of mismatch is large. Instead, this study demonstrates that for tryptophan-flanked peptides the dominant response of a membrane to large mismatch is that the extent of incorporation is reduced, when the peptide is both too short and too long. With increasing mismatch, a smaller fraction of peptide is incorporated into the lipid bilayer, and a larger fraction is present in extramembranous aggregates. Relatively long peptides that remain incorporated in the bilayer have a small tilt angle with respect to the membrane normal. The observed effects depend on the nature of the flanking residues: long tryptophan-flanked peptides do not associate well with thin bilayers, while equisized lysine-flanked peptides associate completely, thus supporting the notion that tryptophan and lysine interact differently with membrane-water interfaces. The different properties that aromatic and charged flanking residues impart on transmembrane protein segments are discussed in relation to protein incorporation in biological systems.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1021/bi000804r
ISSNs: 0006-2960 (print)
ePrint ID: 48608
Date :
Date Event
24 April 2001Published
Date Deposited: 03 Oct 2007
Last Modified: 16 Apr 2017 18:22
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/48608

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