In this paper we examine how the lactose permease, LacY, changes its structure to shuttle molecules of lactose across a cell membrane. The change in conformation is modelled usinga biased computational method called dynamic importance sampling (DIMS) and the results compared to the results of some previously published double electron electron spin resonance (DEER) experiments. We conclude that LacY, as expected, does pass through an occluded intermediate and this is incompatible a simple rigid-body motion as implied by a “rocker-switch” mechanism.
It is published in the Journal of Molecular Biology and is free to download (open access).
