2wit
CRYSTAL STRUCTURE OF THE SODIUM-COUPLED GLYCINE BETAINE SYMPORTER BETP FROM CORYNEBACTERIUM GLUTAMICUM WITH BOUND SUBSTRATECRYSTAL STRUCTURE OF THE SODIUM-COUPLED GLYCINE BETAINE SYMPORTER BETP FROM CORYNEBACTERIUM GLUTAMICUM WITH BOUND SUBSTRATE
Structural highlights
FunctionBETP_CORGL High-affinity uptake of glycine betaine (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedOsmoregulated transporters sense intracellular osmotic pressure and respond to hyperosmotic stress by accumulation of osmolytes to restore normal hydration levels. Here we report the determination of the X-ray structure of a member of the family of betaine/choline/carnitine transporters, the Na(+)-coupled symporter BetP from Corynebacterium glutamicum, which is a highly effective osmoregulated uptake system for glycine betaine. Glycine betaine is bound in a tryptophan box occluded from both sides of the membrane with aromatic side chains lining the transport pathway. BetP has the same overall fold as three unrelated Na(+)-coupled symporters. Whereas these are crystallized in either the outward-facing or the inward-facing conformation, the BetP structure reveals a unique intermediate conformation in the Na(+)-coupled transport cycle. The trimeric architecture of BetP and the break in three-fold symmetry by the osmosensing C-terminal helices suggest a regulatory mechanism of Na(+)-coupled osmolyte transport to counteract osmotic stress. Molecular basis of transport and regulation in the Na(+)/betaine symporter BetP.,Ressl S, Terwisscha van Scheltinga AC, Vonrhein C, Ott V, Ziegler C Nature. 2009 Mar 5;458(7234):47-52. PMID:19262666[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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