The role of TMS 12 in the staphylococcal multidrug efflux protein QacA.

ABSTRACT:

Objectives

To elucidate the importance of a region in QacA predicted to be important in antimicrobial substrate recognition.

Methods

A total of 38 amino acid residues within or flanking putative transmembrane helix segment (TMS) 12 of QacA were individually replaced with cysteine using site-directed mutagenesis. The impact of these mutations on protein expression, drug resistance, transport activity and interaction with sulphhydryl-binding compounds was determined.

Results

Accessibility analysis of cysteine-substituted mutants identified the extents of TMS 12, which allowed for refinement of the QacA topology model. Mutation of Gly-361, Gly-379 and Ser-387 in QacA resulted in reduced resistance to at least one bivalent substrate. Interaction with sulphhydryl-binding c

SUBMITTER: Dashtbani-Roozbehani A 

PROVIDER: S-EPMC10269129 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature