A gate-free pathway for substrate release from the inward-facing state of the Na⁺-galactose transporter.

ABSTRACT: Employing molecular dynamics (MD) simulations, the pathway and mechanism of substrate unbinding from the inward-facing state of the Na(+)-coupled galactose transporter, vSGLT, have been investigated. During a 200-ns equilibrium simulation, repeated spontaneous unbinding events of the substrate from its binding site have been observed. In contrast to the previously proposed gating role of a tyrosine residue (Y263), the unbinding mechanism captured in the present equilibrium simulation does not rely on the displacement and/or rotation of this side chain. Rather, the unbinding involves an initial lateral displacement of the substrate out of the binding site which allows the substrate to completely emerge from the region covered by the side chain of Y263 without any noticeable conformational c

SUBMITTER: Li J 

PROVIDER: S-EPMC3253917 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature