Lipid bilayer composition can influence the orientation of proteorhodopsin in artificial membranes

Ramya Tunuguntla, Mangesh Bangar, Kyunghoon Kim, Pieter Stroeve, Caroline M. Ajo-Franklin, Aleksandr Noy

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Artificial membrane systems allow researchers to study the structure and function of membrane proteins in a matrix that approximates their natural environment and to integrate these proteins in ex vivo devices such as electronic biosensors, thin-film protein arrays, or biofuel cells. Given that most membrane proteins have vectorial functions, both functional studies and applications require effective control over protein orientation within a lipid bilayer. In this work, we explored the role of the bilayer surface charge in determining transmembrane protein orientation and functionality during formation of proteoliposomes. We reconstituted a model vectorial ion pump, proteorhodopsin, in liposomes of opposite charges and varying charge densities and determined the resultant protein orientation. Antibody-binding assay and proteolysis of proteoliposomes showed physical evidence of preferential orientation, and functional assays verified the vectorial nature of ion transport in this system. Our results indicate that the manipulation of lipid composition can indeed control orientation of an asymmetrically charged membrane protein, proteorhodopsin, in liposomes.

Original languageEnglish (US)
Pages (from-to)1388-1396
Number of pages9
JournalBiophysical Journal
Volume105
Issue number6
DOIs
StatePublished - Sep 17 2013
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics

Cite this