Reanalysis of structure/function correlations in the region of transmembrane segments 4 and 5 of the rabbit sodium/glucose cotransporter

Tiemin Liu, Pam Speight, Mel Silverman

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

The predicted topology of the mammalian high-affinity sodium/glucose cotransporter (SGLT1), in the region surrounding transmembrane segments 4 and 5, disagrees with the recent published crystal structure of bacterial SGLT from Vibrio parahaemolyticus (vSGLT). To investigate this issue further, 38 residues from I143 to A180 in the N-terminal half of rabbit SGLT1 were each replaced with cysteine and then expressed in COS-7 cells or Xenopus laevis oocytes. The membrane orientations of the substituted cysteines were determined by treatment with the thiol-specific reagent N-Biotinoylaminoethyl methanethiosulfonate (biotin-MTSEA), combined with the membrane impermeant thiol-specific reagent sodium (2-sulfonatoethyl) methanethiosulfonate (MTSES). The present results combined with previous structure/function studies of SGLT1, suggest that transmembrane domain (TM) 4 of mammalian SGLT1 extends from residue 143-171 and support the topology observed in the crystal structure of vSGLT.

Original languageEnglish (US)
Pages (from-to)133-138
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume378
Issue number1
DOIs
StatePublished - Jan 2 2009

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Keywords

  • Glucose-galactose malabsorption
  • Methanethiosulfonate reagents
  • Secondary structure

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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