Conformation of the pentasaccharide corresponding to the binding site of heparin for antithrombin III.
The conformation in solution of the pentasaccharide methyl glycoside (As-G-A*-Is-AM; 1), which represents the binding site of heparin for Antithrombin III, has been investigated using molecular mechanics and 1H-n.m.r. spectroscopy. The pentasaccharide has a rather rigid (As-G-A*) and a more flexible (Is-AM) region. A simplified model of 1, comprising two conformations, corresponding to the 1C4 and the 2S0 forms of the iduronate residue, and modified at the G-A* glycosidic linkage with respect to the energy minimum, reproduces most of the observed 3J values and n.O.e. enhancements. The possible role in the binding to Antithrombin III of a low-energy conformer, not observed in solution, is discussed.
Ragazzi
M
M
Istituto di Chimica delle Macromolecole del C.N.R., Milano, Italy.
Ferro
D R
DR
Perly
B
B
Sinaÿ
P
P
Petitou
M
M
Choay
J
J
D000990:Antithrombin III; D001665:Binding Sites; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004187:Disaccharides; D005944:Glucosamine; D006493:Heparin; D007067:Iduronic Acid; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009844:Oligosaccharides; D013816:Thermodynamics
D004187:Disaccharides; D009844:Oligosaccharides; D007067:Iduronic Acid; D000990:Antithrombin III; D006493:Heparin; D005944:Glucosamine