Journal
BIOMETALS
Volume 26, Issue 4, Pages 593-607Publisher
SPRINGER
DOI: 10.1007/s10534-013-9628-0
Keywords
CusC(F)BA efflux system; Heavy-metal efflux; Tripartite efflux pump; Multidrug resistance; Resistance-nodulation-cell division; X-ray crystallography
Categories
Ask authors/readers for more resources
Resistance-nodulation-cell division (RND) superfamily efflux systems are responsible for the active transport of toxic compounds from the Gram-negative bacterial cell. These pumps typically assemble as tripartite complexes, spanning the inner and outer membranes of the cell envelope. In Escherichia coli, the CusC(F)BA complex, which exports copper(I) and silver(I) and mediates resistance to these two metal ions, is the only known RND transporter with a specificity for heavy metals. We have determined the crystal structures of both the inner membrane pump CusA and membrane fusion protein CusB, as well as the adaptor-transporter CusBA complex formed by these two efflux proteins. In addition, the crystal structures of the outer membrane channel CusC and the periplasmic metallochaperone CusF have been resolved. Based on these structures, the entire assembled model of the tripartite efflux system has been developed, and this efflux complex should be in the form of CusC(3)-CusB(6)-CusA(3). It has been shown that CusA utilizes methionine clusters to bind and export Cu(I) and Ag(I). This pump is likely to undergo a conformational change, and utilize a relay network of methionine clusters as well as conserved charged residues to extrude the metal ions from the bacterial cell.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available