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J Am Chem Soc. 2009 Mar 25;131(11):3816-7. doi: 10.1021/ja809007f.

Using two fluorescent probes to dissect the binding, insertion, and dimerization kinetics of a model membrane peptide.

Author information

1
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.

Abstract

Helix-helix association within a membrane environment represents one of the fundamental processes in membrane protein folding. However, studying the kinetics of such processes has been difficult because most membrane proteins are insoluble in aqueous solution. Here we present a stopped-flow fluorescence study of the membrane-interaction kinetics of a designed, water-soluble transmembrane (TM) peptide, anti-alpha(IIb), which is known to dimerize in phospholipid bilayers. We show that by using two fluorescent amino acids, tryptophan and p-cyanophenylalanine, we are able to kinetically dissect distinct phases in the peptide-membrane interaction, representing membrane binding, membrane insertion, and TM helix-helix association. Our results further show that the last process occurs on a time scale of seconds, indicating that the association of two TM helices is an intrinsically slow event.

PMID:
19256494
PMCID:
PMC2667230
DOI:
10.1021/ja809007f
[Indexed for MEDLINE]
Free PMC Article

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