Abstract
An alanine to cysteine mutation at position 166 has been introduced by site-directed mutagenesis into the rabbit sodium/glucose transporter (rSGLT1). When expressed in Xenopus laevis oocytes, this mutant transporter (A166C rSGLT1) demonstrates a significantly lower apparent affinity for alpha-methyl glucoside (alphaMG) compared with the wild-type transporter (apparent Km = 0.8 versus 0.15 mM). Using the two-electrode voltage clamp technique, transient currents have also been measured, and for the mutant transporter, the transients induced by large depolarizations exhibit longer time constants than those for wild type. Moreover, the substitution of Ala-166 with a cysteine allows the sulfydryl specific reagent, methanethiosulfonate ethylamine (MTSEA), to react with and alter the function of the transporter. Whereas the wild-type transporter is unaffected by reaction with MTSEA, A166C rSGLT1 has its steady-state currents induced by 1 mM alphaMG inhibited 83% within a minute of exposure to MTSEA. Furthermore, the pre-steady-state transients of the A166C mutant after MTSEA exposure demonstrate much shorter time constants than before while the total amount of charge transferred is only slightly diminished. These results together prov...Continue Reading
References
Mar 1, 1992·Proceedings of the National Academy of Sciences of the United States of America·A G SwickM D Lane
Feb 1, 1990·FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology·S S TateS Udenfriend
Nov 2, 1987·Nature·M A HedigerE M Wright
Oct 3, 1995·Biochemistry·M H Akabas, A Karlin
Jun 7, 1994·Biochemistry·D A Stauffer, A Karlin
Jun 15, 1993·Proceedings of the National Academy of Sciences of the United States of America·D D LooE M Wright
Dec 18, 1995·FEBS Letters·M P LostaoE M Wright
Feb 1, 1996·Nature Genetics·M G MartínE M Wright
Jan 26, 1996·The Journal of Biological Chemistry·E TurkE M Wright
Dec 1, 1995·Biophysical Journal·X Z ChenJ Y Lapointe
Feb 15, 1996·Nucleic Acids Research·A H LundF S Pedersen
Apr 26, 1996·The Journal of Biological Chemistry·M Panayotova-HeiermannE M Wright
Aug 1, 1996·Current Opinion in Cell Biology·E M WrightB A Hirayama
Dec 19, 1995·Biochemistry·J A JavitchJ Chen
Jan 15, 1997·The Journal of Membrane Biology·A HazamaE M Wright
Citations
Oct 26, 1999·The Journal of General Physiology·G LambertH Murer
May 31, 2001·The Journal of General Physiology·G LambertH Murer
May 2, 2008·American Journal of Physiology. Cell Physiology·Tiemin LiuMel Silverman
Nov 18, 2008·Biochemical and Biophysical Research Communications·Tiemin LiuMel Silverman
May 21, 2005·Biochimica Et Biophysica Acta·Dominique G GagnonJean-Yves Lapointe
Jul 9, 2004·Biophysical Journal·Steven A HuntleyMel Silverman
Jan 27, 2009·Biophysical Journal·Tiemin LiuMel Silverman
Feb 20, 2004·American Journal of Physiology. Cell Physiology·Daniel KrofchickMel Silverman
Jun 15, 2000·The Journal of Biological Chemistry·Z XieE M Wright
Oct 29, 1998·The Journal of Biological Chemistry·B Lo, M Silverman