Wang, Jin-Feng and Falke, Joseph J. and Chan, Sunney I. (1986) A proton NMR study of the mechanism of the erythrocyte glucose transporter. Proceedings of the National Academy of Sciences of the United States of America, 83 (10). pp. 3277-3281. ISSN 0027-8424 http://resolver.caltech.edu/CaltechAUTHORS:WANpnas86
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A generalizable 1H NMR technique is developed and used to monitor ß-D-glucose binding to glucose transport sites on erythrocyte membranes. This technique provides resolution of ß-D-glucose binding sites on opposite sides of the membrane, thereby enabling study of recruitment of transport sites from one side of the membrane to the other. Cytochalasin B, which competitively and specifically inhibits glucose binding to the inward-facing glucose transport site, recruits all glucose transport sites on both sides of the membrane to the inward-facing conformation. This result strongly supports a one-site model in which a single transport site alternates between distinct inward- and outward-facing conformations. The rate-limiting step in the transport process is translocation of the transport site between the two conformations, since the ß-D-glucose binding and dissociation events at both the inward- and outward-facing transport sites are shown to be fast compared to the known turnover rate of the glucose transport cycle. A model is presented for the transport machinery in which the glucose molecule binds in a cleft between channel-forming transmembrane helices, and during the transport event a sliding barrier moves past the transport site, thereby exposing the site to the opposite solution compartment.
|Additional Information:||Copyright © 1986 by the National Academy of Sciences. Communicated by John D. Baldeschwieler, January 7, 1986. This work was supported in part by Grant GM 22432 from the National Institute of General Medical Sciences. We acknowledge use of the Southern California Regional High Field Nuclear Magnetic Resonance Facility funded by Grants CHE-7916324 and CHE-8314759 from the National Science Foundation. J.J.F. was a National Science Foundation Predoctoral Fellow. This is contribution no. 7222 from the Arthur Amos Noyes Laboratory of Chemical Physics. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.|
|Subject Keywords:||membrane; binding sites; sugar transport; sliding-barrier model|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||26 Jan 2006|
|Last Modified:||26 Dec 2012 08:44|
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