Lipid composition regulates the orientation of transmembrane helices in HorA, an ABC multidrug transporter.

ABSTRACT: ATP-binding cassette (ABC) transporters constitute a large class of molecular pumps whose central role in chemotherapy resistance has highlighted their clinical relevance. We investigated whether the lipid composition of the membrane affects the function and structure of HorA, a bacterial ABC multidrug transporter. When the transporter was reconstituted in a bilayer where phosphatidylethanolamine (PE), the main lipid of the bacterial membrane, was replaced with phosphatidylcholine (PC), ATP hydrolysis and substrate transport became uncoupled. Although ATPase activity was maintained, HorA lost its ability to extrude the prototypical substrate Hoechst33342. Attenuated Total Reflection-Fourier Transform Infrared spectroscopy (ATR-FTIR) revealed that, although the secondary structure of the pr

SUBMITTER: Gustot A 

PROVIDER: S-EPMC2863179 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature