2xq2

Structure of the K294A mutant of vSGLT

spinqualitylabelsall models 2xq2, resolution 2.73Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xq2 is a 2 chain structure with sequence from Vibrio parahaemolyticus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.73Å Ligands: PEG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SGLT_VIBPH Actively transports glucose into cells by Na(+) cotransport. Publication Abstract from PubMed Membrane co-transport proteins that use a five-helix inverted repeat motif have recently emerged as one of the largest structural classes of secondary active transporters. However, despite many structural advances there is no clear evidence of how ion and substrate transport are coupled. Here we report a comprehensive study of the sodium/galactose transporter from Vibrio parahaemolyticus (vSGLT), consisting of molecular dynamics simulations, biochemical characterization and a new crystal structure of the inward-open conformation at a resolution of 2.7 A. Our data show that sodium exit causes a reorientation of transmembrane helix 1 that opens an inner gate required for substrate exit, and also triggers minor rigid-body movements in two sets of transmembrane helical bundles. This cascade of events, initiated by sodium release, ensures proper timing of ion and substrate release. Once set in motion, these molecular changes weaken substrate binding to the transporter and allow galactose readily to enter the intracellular space. Additionally, we identify an allosteric pathway between the sodium-binding sites, the unwound portion of transmembrane helix 1 and the substrate-binding site that is essential in the coupling of co-transport. The mechanism of sodium and substrate release from the binding pocket of vSGLT.,Watanabe A, Choe S, Chaptal V, Rosenberg JM, Wright EM, Grabe M, Abramson J Nature. 2010 Dec 5. PMID:21131949 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Symporter 3D structures

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