Alternating access of the putative substrate-binding chamber in the ABC transporter MsbA.

ABSTRACT: MsbA is an ATP-binding cassette transporter from Escherichia coli that is involved in trafficking lipid A across the inner membrane. ATP-binding cassette transporters harness the free energy of ATP binding and hydrolysis to drive the uphill translocation of substrates against their concentration gradients. A model of protein motion coupling energy input to work was inspired by crystallographic snapshots of MsbA. Central to this model is a switch in the accessibility of a transmembrane chamber, implicated in substrate binding, from an inward- to an outward-facing configuration. Here, we used spin labeling and electron paramagnetic resonance spectroscopy to systematically explore rearrangements in MsbA structure during the ATP hydrolysis cycle. Spin-label accessibility and local dynamics wer

SUBMITTER: Zou P 

PROVIDER: S-EPMC2760602 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature