کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10798150 | 1053300 | 2005 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Membrane topology of loop 13-14 of the Na+/glucose cotransporter (SGLT1): A SCAM and fluorescent labelling study
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کلمات کلیدی
Na+/glucose cotransportervesicular stomatitis virus G proteinVSVGMTSSGLT1MTSEAMTSESTMSMTSET2-Aminoethyl methanethiosulfonate hydrobromide - 2-آمینه اتیل متانتیوسولفونات هیدرو بورومیدamino acid - آمینو اسیدElectrophysiology - الکتروفیزیولوژیtransmembrane segment - بخش غشاییTopology - توپولوژیSubstituted cysteine accessibility method - روش دسترسی به سیتستین جایگزینFluorescence - فلورسنسPhlorizin - فلویزینMethanethiosulfonate - متانتیوسولفوناتMembrane potential - پتانسیل غشاء SCAM - کلاهبرداری
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Membrane topology of loop 13-14 of the Na+/glucose cotransporter (SGLT1): A SCAM and fluorescent labelling study Membrane topology of loop 13-14 of the Na+/glucose cotransporter (SGLT1): A SCAM and fluorescent labelling study](/preview/png/10798150.png)
چکیده انگلیسی
The accessibility of the hydrophilic loop between putative transmembrane segments XIII and XIV of the Na+/glucose cotransporter (SGLT1) was studied in Xenopus oocytes, using the substituted cysteine accessibility method (SCAM) and fluorescent labelling. Fifteen cysteine mutants between positions 565 and 664 yielded cotransport currents of similar amplitude than the wild-type SGLT1 (wtSGLT1). Extracellular, membrane-impermeant MTSES(â) and MTSET(+) had no effect on either cotransport or Na+ leak currents of wtSGLT1 but 9 mutants were affected by MTSES and/or MTSET. We also performed fluorescent labelling on SGLT1 mutants, using tetramethylrhodamine-5-maleimide and showed that positions 586, 588 and 624 were accessible. As amino acids 604 to 610 in SGLT1 have been proposed to form part of a phlorizin (Pz) binding site, we measured the KiPz and KmαMG for wtSGLT1 and for cysteine mutants at positions 588, 605-608 and 625. Although mutants A605C, Y606C and D607C had slightly higher KiPz values than wtSGLT1 with minimal changes in KmαMG, the effects were modest and do not support the original hypothesis. We conclude that the large, hydrophilic loop near the carboxyl terminus of SGLT1 is thus accessible to the external solution but does not appear to play a major part in the binding of phlorizin.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Biomembranes - Volume 1712, Issue 2, 1 July 2005, Pages 173-184
Journal: Biochimica et Biophysica Acta (BBA) - Biomembranes - Volume 1712, Issue 2, 1 July 2005, Pages 173-184
نویسندگان
Dominique G. Gagnon, Andrea Holt, Francis Bourgeois, Bernadette Wallendorff, Michael J. Coady, Jean-Yves Lapointe,