EmrE from Escherichia coli is a member of the small multidrug resistance protein family that oligomerizes to export hydrophobic cationic antimicrobials by utilizing the proton motive force. We studied the helix-helix interactions of the four transmembrane (TM) segments of EmrE to determine how this protein might assemble into its oligomeric forms. Using a combination of biochemical and biophysical techniques, we assessed the oligomerization propensities of Lys-tagged EmrE TM peptides in membrane-mimetic environments. Our results established that each of the TMs of EmrE display detergent-sensitive self-association, but in particular, TM2 had the greatest dimerization capability that was not completely abolished even by scrambling the native sequence. Mutations made to TM2 in full-length EmrE also revealed that efflux-defective mutations are located on one face of the helix. These findings reveal another potential oligomerization site for EmrE - and perhaps SMRs - and may provide a target for development of novel efflux-inhibitors.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/43340 |
| Date | 11 December 2013 |
| Creators | Wang, Jun |
| Contributors | Deber, Charles M. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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