4oaa

Crystal structure of E. coli lactose permease G46W,G262W bound to sugar

spinqualitylabelsall models 4oaa, resolution 3.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4oaa is a 2 chain structure with sequence from Escherichia coli str. K-12 substr. DH10B. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GAL, PRD_900027, YIO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Here we describe the X-ray crystal structure of a double-Trp mutant (Gly46-->Trp/Gly262-->Trp) of the lactose permease of Escherichia coli (LacY) with a bound, high-affinity lactose analog. Although thought to be arrested in an open-outward conformation, the structure is almost occluded and is partially open to the periplasmic side; the cytoplasmic side is tightly sealed. Surprisingly, the opening on the periplasmic side is sufficiently narrow that sugar cannot get in or out of the binding site. Clearly defined density for a bound sugar is observed at the apex of the almost occluded cavity in the middle of the protein, and the side chains shown to ligate the galactopyranoside strongly confirm more than two decades of biochemical and spectroscopic findings. Comparison of the current structure with a previous structure of LacY with a covalently bound inactivator suggests that the galactopyranoside must be fully ligated to induce an occluded conformation. We conclude that protonated LacY binds d-galactopyranosides specifically, inducing an occluded state that can open to either side of the membrane. Structure of sugar-bound LacY.,Kumar H, Kasho V, Smirnova I, Finer-Moore JS, Kaback HR, Stroud RM Proc Natl Acad Sci U S A. 2014 Feb 4;111(5):1784-8. doi: 10.1073/pnas.1324141111., Epub 2014 Jan 22. PMID:24453216 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Symporter 3D structures

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