Funnel-like hexameric assembly of the periplasmic adapter protein in the tripartite multidrug efflux pump in gram-negative bacteria.

ABSTRACT: Gram-negative bacteria expel diverse toxic chemicals through the tripartite efflux pumps spanning both the inner and outer membranes. The Escherichia coli AcrAB-TolC pump is the principal multidrug exporter that confers intrinsic drug tolerance to the bacteria. The inner membrane transporter AcrB requires the outer membrane factor TolC and the periplasmic adapter protein AcrA. However, it remains ambiguous how the three proteins are assembled. In this study, a hexameric model of the adapter protein was generated based on the propensity for trimerization of a dimeric unit, and this model was further validated by presenting its channel-forming property that determines the substrate specificity. Genetic, in vitro complementation, and electron microscopic studies provided evidence for the bind

SUBMITTER: Xu Y 

PROVIDER: S-EPMC3093866 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature