Ligand-induced differences in secondary structure of the Vibrio parahaemolyticus Na+/galactose cotransporter.
A detailed structural study of the prokaryotic sodium/galactose transporter (vSGLT) from Vibrio parahaemolyticus using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy reveals stepwise increases in alpha-helicity upon binding of sodium and D-galactose. These increases in helicity correlate with decreases in beta-structural elements. The changes are accompanied by stepwise reductions in the degree of H/D exchange (HDX), suggesting reduced accessibility of water to the protein backbone. The data demonstrate discrete conformational changes from one intermediate to the next during the catalytic cycle of the protein and are interpreted in a model of the symport reaction mechanism.
le Coutre
Johannes
J
Nestlé Research Center Lausanne, Vers-Chez-Les-Blanc, 1000 Lausanne 26, Switzerland. johannes.le-coutre@rdls.nestle.com
Turk
Eric
E
Kaback
H Ronald
HR
Wright
Ernest M
EM
D000577:Amides / Q000737:chemistry; D001665:Binding Sites; D002384:Catalysis; D017666:Deuterium Oxide / Q000737:chemistry; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006859:Hydrogen / Q000737:chemistry; D008024:Ligands; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D012964:Sodium / Q000378:metabolism; D051269:Sodium-Glucose Transporter 1; D017550:Spectroscopy, Fourier Transform Infrared; D014736:Vibrio parahaemolyticus / Q000737:chemistry* / Q000378:metabolism*
D000577:Amides; D008024:Ligands; D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D051269:Sodium-Glucose Transporter 1; D006859:Hydrogen; D012964:Sodium; D005947:Glucose; D017666:Deuterium Oxide; D005690:Galactose