Surface-supported bilayers with transmembrane proteins: Role of the polymer cushion revisited

Mikhail Merzlyakov, Edwin Li, Ivan Gitsov, Kalina A Hristova

Research output: Contribution to journalArticle

Abstract

Protein lateral mobility in surface-supported bilayers is often much lower than the mobility of the lipids. In the present study we explore whether the incorporation of a PEG cushion between the bilayer and the substrate increases the lateral mobility of transmembrane proteins in bilayers produced via directed assembly, a method based on Langmuir-Blodgett deposition techniques. In our experiments, the PEG cushions were incorporated by adding PEG lipids to the protein/lipid monolayer at the air/water interface, at the first step of bilayer assembly. The protein and lipid mobilities in 160 different bilayers, with various PEG molecular weights and PEG lipid concentrations, were measured and compared. We found that the measured diffusion coefficients do not depend on the PEG molecular weight or the PEG lipid concentration and are very similar to the values measured in the absence of PEG. Therefore, contrary to our expectations, we found that a PEG cushion does not necessarily increase protein mobility, suggesting that the low protein mobility is not a consequence of protein-substrate interactions. Furthermore, we showed that the low protein mobility is not due to protein aggregation. The major determinant of protein mobility in surface-supported bilayer systems appears to be the method of bilayer assembly. While proteins were always mobile if the bilayers were prepared using the directed assembly method, in the presence and absence of a PEG cushion, other bilayer assembly protocols resulted in complete lack of protein mobility.

Original languageEnglish (US)
Pages (from-to)10145-10151
Number of pages7
JournalLangmuir
Volume22
Issue number24
DOIs
StatePublished - Nov 21 2006

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cushions
Polymers
Polyethylene glycols
proteins
Proteins
polymers
Lipids
lipids
assembly
molecular weight
Molecular weight
Substrates
determinants
Monolayers

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Surface-supported bilayers with transmembrane proteins : Role of the polymer cushion revisited. / Merzlyakov, Mikhail; Li, Edwin; Gitsov, Ivan; Hristova, Kalina A.

In: Langmuir, Vol. 22, No. 24, 21.11.2006, p. 10145-10151.

Research output: Contribution to journalArticle

Merzlyakov, Mikhail ; Li, Edwin ; Gitsov, Ivan ; Hristova, Kalina A. / Surface-supported bilayers with transmembrane proteins : Role of the polymer cushion revisited. In: Langmuir. 2006 ; Vol. 22, No. 24. pp. 10145-10151.
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