Conformational cycle of the ABC transporter MsbA in liposomes: detailed analysis using double electron-electron resonance spectroscopy.

ABSTRACT: Driven by the energy of ATP binding and hydrolysis, ATP-binding cassette transporters alternate between inward- and outward-facing conformations, allowing vectorial movement of substrates. Conflicting models have been proposed to describe the conformational motion underlying this switch in access of the transport pathway. One model, based on three crystal structures of the lipid flippase MsbA, envisions a large-amplitude motion that disengages the nucleotide-binding domains and repacks the transmembrane helices. To test this model and place the crystal structures in a mechanistic context, we use spin labeling and double electron-electron resonance spectroscopy to define the nature and amplitude of MsbA conformational change during ATP hydrolysis cycle. For this purpose, spin labels were in

SUBMITTER: Zou P 

PROVIDER: S-EPMC2760609 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature