4doj | pdb_00004doj

Crystal structure of BetP in outward-facing conformation

spinqualitylabelsall models 4doj, resolution 3.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4doj is a 3 chain structure with sequence from "micrococcus_glutamicus"_kinoshita_et_al._1958 "micrococcus glutamicus" kinoshita et al. 1958. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CHT, CL, PGT Gene: betP, Cgl0892, cg1016 ("Micrococcus glutamicus" Kinoshita et al. 1958) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [BETP_CORGL] High-affinity uptake of glycine betaine (By similarity). Publication Abstract from PubMed Betaine and Na(+) symport has been extensively studied in the osmotically regulated transporter BetP from Corynebacterium glutamicum, a member of the betaine/choline/carnitine transporter family, which shares the conserved LeuT-like fold of two inverted structural repeats. BetP adjusts its transport activity by sensing the cytoplasmic K(+) concentration as a measure for hyperosmotic stress via the osmosensing carboxy-terminal domain. BetP needs to be in a trimeric state for communication between individual protomers through several intratrimeric interaction sites. Recently, crystal structures of inward-facing BetP trimers have contributed to our understanding of activity regulation on a molecular level. Here we report new crystal structures, which reveal two conformationally asymmetric BetP trimers, capturing among them three distinct transport states. We observe a total of four new conformations at once: an outward-open apo and an outward-occluded apo state, and two closed transition states-one in complex with betaine and one substrate-free. On the basis of these new structures, we identified local and global conformational changes in BetP that underlie the molecular transport mechanism, which partially resemble structural changes observed in other sodium-coupled LeuT-like fold transporters, but show differences we attribute to the osmolytic nature of betaine, the exclusive substrate specificity and the regulatory properties of BetP. Alternating-access mechanism in conformationally asymmetric trimers of the betaine transporter BetP.,Perez C, Koshy C, Yildiz O, Ziegler C Nature. 2012 Sep 2. doi: 10.1038/nature11403. PMID:22940865 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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