FEATURES

FAMILY

resistance-nodulation-cell division (RND) (TC 2.A.6) family

DESCRIPTION

Also known as MEXB_PSEAE, mexB. The inner membrane transporter component of the MexAB-OprM efflux system that confers multidrug resistance. Also functions as the major efflux pump for n-hexane and p-xylene efflux. Over-expression of the pump increases antibiotic and solvent efflux capacities. Implicated in the secretion of the siderophore pyoverdine., The ability to export antibiotics and solvents is dramatically decreased in the presence of the proton conductor carbonyl cyanide m-chlorophenylhydrazone (CCCP), showing that an energized inner membrane is required for efflux. It is thought that the MexB subunit is a proton antiporter. Component of the MexAB-OprM multidrug efflux complex composed of an unknown number of MexA subunits, MexB and an OprM homotrimer. The MexA subunits are thought to form a barrel between the MexB inner membrane transporter and the trimeric OprM outer membrane channel protein which allows substrates to pass directly from the cytoplasm to the external mileu. How the MexA subunits interact with OprM and MexB, and how the OprM channel is opened is unknown.

EXTERNAL LINKS

mexB

Multidrug resistance protein MexB

mexB

Molecular Synopsis