Author:
Moseng Mitchell A.,Klenotic Philip A.,Yu Edward W.
Abstract
AbstractGram‐negative bacteria utilize the resistance‐nodulation‐cell division (RND) superfamily of efflux pumps to remove toxic compounds from the cell. TheEscherichia coliCusA membrane protein is responsible for recognizing and extruding biocidal Cu(I) and Ag(I) ions. This membrane protein belongs to the heavy‐metal efflux (HME) subfamily of RND efflux transporters. We use single‐particle cryo‐electron microscopy (cryo‐EM) to solve four different structures of the trimeric CusA heavy‐metal efflux pump in the presence of Cu(I). We discovered that different CusA protomers within the trimer are able to bind Cu(I) ions simultaneously. Our structural data allow us to propose a mechanism for ion transport where each CusA protomer functions independently within the trimer.