Conformational behavior of alpha-D-mannopyranosyl-(1-->6)-alpha,beta-D-mannose complexed with two mannose-binding plant lectins, Allium sativam agglutinin I and concanavalin A, using NMR and molecular modeling techniques.
Herein, we report the intrinsic conformational preferences of alpha-d-Manp-(1-->6)-alpha,beta-d-Manp, (1) in the free state and as two (ASAI and ConA) lectin-bound forms. NMR spectroscopy and molecular dynamics techniques are used as 3D-structural determination tools. In free form disaccharide 1 displays a fair amount of conformational freedom, with one major (phi/psi 95 +/- 30 degrees/195 +/- 20 degrees and one minor (95 +/- 30 degrees/70 +/- 20 degrees) conformations around the glycosidic linkage and around the omega angle, both the gg and gt rotamers are almost equally populated. This is a first report of a three-dimensional structure of 1 bound with ASAI. Both lectins recognize a major phi/psi 95 +/- 30 degrees/200 +/- 30 degrees conformer with the ligand showing more flexibility in the binding site of ConA. Comparison of the mode of binding of the two lectins explains the differences in observed specificities.
Mazumder
Parichita
P
Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, India.
Mukhopadhyay
Chaitali
C
D000042:Absorption; D002236:Carbohydrate Conformation; D003208:Concanavalin A / Q000737:chemistry / Q000378:metabolism*; D004187:Disaccharides / Q000737:chemistry* / Q000378:metabolism*; D005737:Garlic / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D037601:Mannose-Binding Lectin / Q000737:chemistry / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D037121:Plant Lectins / Q000737:chemistry / Q000378:metabolism*
D004187:Disaccharides; D037601:Mannose-Binding Lectin; D037121:Plant Lectins; C547763:alpha-D-mannopyranosyl-(1-6)-alpha,beta-D-mannose; D003208:Concanavalin A; D008358:Mannose