Site-directed disulfide cross-linking to probe conformational changes of a transporter during its functional cycle: Escherichia coli AcrB multidrug exporter as an example.

ABSTRACT: Many proteins, especially transporters, are thought to undergo large conformational alterations during their functional cycle. Since X-ray crystallography usually gives only the most stable conformation, other methods are needed to probe this conformational change. Site-directed disulfide cross-linking is often very useful for this purpose. We illustrate this by using the Escherichia coli AcrB, a proton-motive-force-dependent multidrug efflux transporter. Crystallographic studies of the asymmetric trimer of AcrB suggest that each protomer in the trimeric assembly goes through a cycle of conformational changes during drug export (functional rotation hypothesis). Site-directed disulfide cross-linking between those residues that come close to each other in only one stage in the cycle inactiva

SUBMITTER: Takatsuka Y 

PROVIDER: S-EPMC2915569 | biostudies-literature | 2010

REPOSITORIES: biostudies-literature