GLUT1 transmembrane glucose pathway. Affinity labeling with a transportable D-glucose diazirine

J Biol Chem. 1996 Mar 1;271(9):5225-30. doi: 10.1074/jbc.271.9.5225.

Abstract

We synthesized a transportable diazirine derivative of D-glucose,3-deoxy-3,3-azi-D-glucopyranose (3-DAG), and studied its interaction with purified human erythrocyte facilitative glucose transporter, GLUT1. 3-DAG was rapidly transported into human erythrocytes and their resealed ghosts in the dark via a mercuric chloride-inhibitable mechanism and with a speed comparable with that of 3-O-methyl-D-glucose (3-OMG). The rate of 3-DAG transport in resealed ghosts was a saturable function of 3-DAG concentration with an apparent Km of 3.2 mM and the Vmax of 3.2 micromol/s/ml. D-Glucose inhibited the 3-DAG flux competitively with an apparent KI of 11 mM. Cytochalasin B inhibited this 3-DAG flux in a dose-dependent manner with an estimated KI of 2.4 x 10(-7) M. Cytochalasin E had no effect. These findings clearly establish that 3-DAG is a good substrate of GLUT1. UV irradiation of purified GLUT1 in liposomes in the presence of 3-DAG produced a significant covalent incorporation of 3-DAG into glut1, and 200 mM D-glucose abolished this 3-dag incorporation. Analyses of trypsin and endoproteinase Lys-C digestion of 3-DAG-photolabeled GLUT1 revealed that the cleavage products corresponding to the residues 115 183, 256 300, and 301 451 of the GLUT1 sequence were labeled by 3-DAG, demonstrating that not only the C-terminal half but also the N-terminal half of the transmembrane domain participate in the putative substrate channel formation. 3-DAG may be useful in further identification of the amino acid residues that form the substrate channel of this and other members of the facilitative glucose transporter family.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Affinity Labels / metabolism
  • Amino Acid Sequence
  • Azo Compounds
  • Binding Sites
  • Biological Transport
  • Blood Glucose / metabolism
  • Erythrocyte Membrane / metabolism*
  • Erythrocytes / metabolism
  • Glucose / analogs & derivatives
  • Glucose Transporter Type 1
  • Humans
  • Kinetics
  • Molecular Sequence Data
  • Monosaccharide Transport Proteins / blood*
  • Monosaccharide Transport Proteins / chemistry
  • Monosaccharide Transport Proteins / isolation & purification
  • Peptide Fragments / chemistry
  • Peptide Fragments / isolation & purification

Substances

  • 3-deoxy-3,3-aziglucopyranose
  • Affinity Labels
  • Azo Compounds
  • Blood Glucose
  • Glucose Transporter Type 1
  • Monosaccharide Transport Proteins
  • Peptide Fragments
  • SLC2A1 protein, human
  • Glucose