Helical unwinding and side-chain unlocking unravel the outward open conformation of the melibiose transporter.

ABSTRACT: Molecular dynamics simulations have been used to study the alternate access mechanism of the melibiose transporter from Escherichia coli. Starting from the outward-facing partially occluded form, 2 out of 12 simulations produced an outward full open form and one partially open, whereas the rest yielded fully or partially occluded forms. The shape of the outward-open form resembles other outward-open conformations of secondary transporters. During the transporter opening, conformational changes in some loops are followed by changes in the periplasm region of transmembrane helix 7. Helical curvature relaxation and unlocking of hydrophobic and ionic locks promote the outward opening of the transporter making accessible the substrate binding site. In particular, FRET studies on mutants of cons

SUBMITTER: Wang LY 

PROVIDER: S-EPMC5034317 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature