EmrE dimerization depends on membrane environment. Biochim Biophys Acta 2014 Jul;1838(7):1817-22
Date
04/01/2014Pubmed ID
24680655Pubmed Central ID
PMC4061694DOI
10.1016/j.bbamem.2014.03.013Scopus ID
2-s2.0-84899042377 (requires institutional sign-in at Scopus site) 11 CitationsAbstract
The small multi-drug resistant (SMR) transporter EmrE functions as a homodimer. Although the small size of EmrE would seem to make it an ideal model system, it can also make it challenging to work with. As a result, a great deal of controversy has surrounded even such basic questions as the oligomeric state. Here we show that the purified protein is a homodimer in isotropic bicelles with a monomer-dimer equilibrium constant (KMD(2D)) of 0.002-0.009mol% for both the substrate-free and substrate-bound states. Thus, the dimer is stabilized in bicelles relative to detergent micelles where the KMD(2D) is only 0.8-0.95mol% (Butler et al. 2004). In dilauroylphosphatidylcholine (DLPC) liposomes KMD(2D) is 0.0005-0.0008mol% based on Förster resonance energy transfer (FRET) measurements, slightly tighter than bicelles. These results emphasize the importance of the lipid membrane in influencing dimer affinity.
Author List
Dutta S, Morrison EA, Henzler-Wildman KAAuthor
Emma A. Morrison PhD Associate Professor in the Biochemistry department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AntiportersBiological Transport
Escherichia coli
Escherichia coli Proteins
Lipid Bilayers
Liposomes
Membrane Lipids
Micelles
Protein Multimerization
