2v8n
Wild-type Structure of Lactose PermeaseWild-type Structure of Lactose Permease
Structural highlights
FunctionLACY_ECOLI Responsible for transport of beta-galactosides into the cell, with the concomitant import of a proton (symport system). 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 PubMedHere we describe an x-ray structure of wild-type lactose permease (LacY) from Escherichia coli determined by manipulating phospholipid content during crystallization. The structure exhibits the same global fold as the previous x-ray structures of a mutant that binds sugar but cannot catalyze translocation across the membrane. LacY is organized into two six-helix bundles with twofold pseudosymmetry separated by a large interior hydrophilic cavity open only to the cytoplasmic side and containing the side chains important for sugar and H(+) binding. To initiate transport, binding of sugar and/or an H(+) electrochemical gradient increases the probability of opening on the periplasmic side. Because the inward-facing conformation represents the lowest free-energy state, the rate-limiting step for transport may be the conformational change leading to the outward-facing conformation. Structural determination of wild-type lactose permease.,Guan L, Mirza O, Verner G, Iwata S, Kaback HR Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15294-8. Epub 2007 Sep 19. PMID:17881559[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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