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2v8n
From Proteopedia
WILD-TYPE STRUCTURE OF LACTOSE PERMEASE
Overview
Here 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.
About this Structure
2V8N is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
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 Page seeded by OCA on Sun May 4 18:22:33 2008
