Open AccessMutations affecting substrate specificity of the Bacillus subtilis multidrug transporter Bmr
Author(s) -
Katya A. Klyachko,
Shimon Schuldiner,
Alexander A. Neyfakh
Publication year - 1997
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.179.7.2189-2193.1997
Subject(s) - bacillus subtilis , biology , major facilitator superfamily , transporter , efflux , mutant , biochemistry , bacteria , multiple drug resistance , atp binding cassette transporter , microbiology and biotechnology , genetics , gene , antibiotics
The Bacillus subtilis multidrug transporter Bmr, a member of the major facilitator superfamily of transporters, causes the efflux of a number of structurally unrelated toxic compounds from cells. We have shown previously that the activity of Bmr can be inhibited by the plant alkaloid reserpine. Here we demonstrate that various substitutions of residues Phe143 and Phe306 of Bmr not only reduce its sensitivity to reserpine inhibition but also significantly change its substrate specificity. Cross-resistance profiles of bacteria expressing mutant forms of the transporter differ from each other and from the cross-resistance profile of cells expressing wild-type Bmr. This result strongly suggests that Bmr interacts with its transported drugs directly, with residues Phe143 and Phe306 likely to be involved in substrate recognition.