Asymmetry in the homodimeric ABC transporter MsbA recognized by a DARPin.

ABSTRACT: ABC transporters harness the energy from ATP binding and hydrolysis to translocate substrates across the membrane. Binding of two ATP molecules at the nucleotide binding domains (NBDs) leads to the formation of an outward-facing state. The conformational changes required to reset the transporter to the inward-facing state are initiated by sequential hydrolysis of the bound nucleotides. In a homodimeric ABC exporter such as MsbA responsible for lipid A transport in Escherichia coli, sequential ATP hydrolysis implies the existence of an asymmetric conformation. Here we report the in vitro selection of a designed ankyrin repeat protein (DARPin) specifically binding to detergent-solubilized MsbA. Only one DARPin binds to the homodimeric transporter in the absence as well as in the presence of

SUBMITTER: Mittal A 

PROVIDER: S-EPMC3370220 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature