Permease
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Reports from University of California, Department of Physiology advance knowledge in permease
2007 OCT 22 -- Investigators publish new data in the report 'Structural determination of wild-type lactose permease.' "'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," scientists in the United States report. "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," wrote L. Guan and colleagues, University of California, Department of Physiology. The researchers concluded: "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." Guan and colleagues published their study in Proceedings of the National Academy of Sciences of the United States of America (Structural determination of wild-type lactose permease. Proceedings of the National Academy of Sciences of the United States of America, 2007;104(39):15294-8). For more information, contact L. Guan, University of California, Dept. of Physiology, Los Angeles, CA 90095-1662 USA.. Publisher contact information for the journal Proceedings of the National Academy of Sciences of the United States of America is: National Acad Sciences, 2101 Constitution Avenue NW, Washington, DC 20418, USA. Keywords: United States, Los Angeles, Enzymology, Permease. This article was prepared by Proteomics Weekly editors from staff and other reports. Copyright 2007, Proteomics Weekly via NewsRx.com.
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