Determination of the solution conformation of D-gluco-dihydroacarbose, a high-affinity inhibitor bound to glucoamylase by transferred NOE NMR spectroscopy.
The determination of the bound solution conformation of D-gluco-dihydroacarbose (GAC), a tight-binding inhibitor of several glycosidase and amylase enzymes, by glucoamylase is described. Transferred NOE NMR experiments and line-broadening effects indicate that GAC is bound in a conformation resembling that observed in the crystal structure. This contrasts with the predominant conformation of GAC when free in solution. The NMR results also suggest regions on the carbohydrate that are in close contact with the protein. The determination of the bound solution conformation of GAC by glucoamylase using transferred NOE (trNOE) measurements is a significant achievement given the high affinity constant (Ka = 3 x 10(7) M(-1)) for this receptor-ligand pair. It is striking that the off-rate for complexation is still sufficiently high to permit observation of trNOEs.
Weimar
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Institut für Chemie, Medizinische Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany. thomas.weimer@chemie.mu-luebeck.de
Petersen
B O
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Svensson
B
B
Pinto
B M
BM
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D005087:Glucan 1,4-alpha-Glucosidase / Q000037:antagonists & inhibitors / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D012996:Solutions / Q000737:chemistry; D013329:Structure-Activity Relationship; D014312:Trisaccharides / Q000737:chemistry* / Q000494:pharmacology
D004791:Enzyme Inhibitors; D012996:Solutions; D014312:Trisaccharides; C052108:dihydroacarbose; D005087:Glucan 1,4-alpha-Glucosidase