Identification of the third Na+ site and the sequence of extracellular binding events in the glutamate transporter.

ABSTRACT: The transport cycle in the glutamate transporter (GlT) is catalyzed by the cotransport of three Na(+) ions. However, the positions of only two of these ions (Na1 and Na2 sites) along with the substrate have been captured in the crystal structures reported for both the outward-facing and the inward-facing states of Glt(ph). Characterizing the third ion binding site (Na3) is necessary for structure-function studies attempting to investigate the mechanism of transport in GlTs at an atomic level, particularly for the determination of the sequence of the binding events during the transport cycle. In this study, we report a series of molecular dynamics simulations performed on various bound states of Glt(ph) (the apo state, as well as in the presence of Na(+), the substrate, or both), which have

SUBMITTER: Huang Z 

PROVIDER: S-EPMC2931724 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature