This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Krofchick, D. Articles by Silverman, M. Search for Related Content PubMed PubMed Citation Articles by Krofchick, D. Articles by Silverman, M.

Investigating the Conformational States of the Rabbit Na⁺/Glucose Cotransporter

Institute of Biomaterials and Biomedical Engineering and Canadian Institutes for Health Research Group in Membrane Biology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada

Correspondence: Address reprint requests to Mel Silverman, University of Toronto, Med. Sci. Bldg., Rm. 7207, Toronto, ON M5S 1A8, Canada. Tel.: 416-978-7189; Fax: 416-971-2132; E-mail: melvin.silverman{at}utoronto.ca.

The Na⁺ and voltage-dependence of transient rabbit Na⁺/glucose cotransporter (rSGLT1) kinetics was studied with the two-electrode voltage-clamp technique and Xenopus laevis oocytes. Using step changes in membrane potential, in the absence of glucose but with 100 or 10 mM Na⁺, transient currents were measured corresponding to binding/debinding of Na⁺ and conformational changes of the protein. Previously, only a single time constant has been published for rSGLT1. We, however, observed three decay components; a fast (_f, 0.5–1 ms) voltage- and Na⁺-independent decay, and medium (_m, 0.5–4 ms) and slow (_s, 8–50 ms) voltage- and Na⁺-dependent decays. Transient currents were simulated and fit using a four-state model to obtain kinetic parameters for the system. The four-state model was able to reconstitute an assortment of experimental data.

This article has been cited by other articles:

				T. Liu, B. Lo, P. Speight, and M. Silverman Transmembrane IV of the high-affinity sodium-glucose cotransporter participates in sugar binding Am J Physiol Cell Physiol, July 1, 2008; 295(1): C64 - C72. [Abstract] [Full Text] [PDF]

				D. G. Gagnon, C. Frindel, and J.-Y. Lapointe Effect of Substrate on the Pre-Steady-State Kinetics of the Na+/Glucose Cotransporter Biophys. J., January 15, 2007; 92(2): 461 - 472. [Abstract] [Full Text] [PDF]

				D. G. Gagnon, P. Bissonnette, and J.-Y. Lapointe Identification of a Disulfide Bridge Linking the Fourth and the Seventh Extracellular Loops of the Na+/Glucose Cotransporter J. Gen. Physiol., January 30, 2006; 127(2): 145 - 158. [Abstract] [Full Text] [PDF]

				D. D.F. Loo, B. A. Hirayama, A. Cha, F. Bezanilla, and E. M. Wright Perturbation Analysis of the Voltage-sensitive Conformational Changes of the Na+/Glucose Cotransporter J. Gen. Physiol., December 28, 2004; 125(1): 13 - 36. [Abstract] [Full Text] [PDF]

				S. A. Huntley, D. Krofchick, and M. Silverman Position 170 of Rabbit Na+/Glucose Cotransporter (rSGLT1) Lies in the Na+ Pathway; Modulation of Polarity/Charge at this Site Regulates Charge Transfer and Carrier Turnover Biophys. J., July 1, 2004; 87(1): 295 - 310. [Abstract] [Full Text] [PDF]

				D. Krofchick, S. A. Huntley, and M. Silverman Transition states of the high-affinity rabbit Na+/glucose cotransporter SGLT1 as determined from measurement and analysis of voltage-dependent charge movements Am J Physiol Cell Physiol, July 1, 2004; 287(1): C46 - C54. [Abstract] [Full Text] [PDF]