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Functional response of the small multidrug resistance protein EmrE to mutations in transmembrane helix 2
Author(s) -
Wang Jun,
Rath Arianna,
Deber Charles M.
Publication year - 2014
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2014.08.018
Subject(s) - transmembrane protein , transmembrane domain , conserved sequence , escherichia coli , biology , multiple drug resistance , membrane protein , protein structure , peptide sequence , biophysics , biochemistry , genetics , amino acid , membrane , gene , drug resistance , receptor
Escherichia coli EmrE is a small multidrug resistance protein encompassing four transmembrane (TM) sequences that oligomerizes to confer resistance to antimicrobials. Here we examined the effects on in vivo protein accumulation and ethidium resistance activity of single residue substitutions at conserved and variable positions in EmrE transmembrane segment 2 (TM2). We found that activity was reduced when conserved residues localized to one TM2 surface were replaced. Our findings suggest that conserved TM2 positions tolerate greater residue diversity than conserved sites in other EmrE TM sequences, potentially reflecting a source of substrate polyspecificity.