Free energy surfaces for the alpha(1 --> 4)-glycosidic linkage: implications for polysaccharide solution structure and dynamics.
We present a potential of mean force surface for rotation about phi and psi dihedral angles of the alpha(1 --> 4)-glycosidic linkage in the maltose disaccharide (4-O-alpha-d-glucopyranosyl-d-glucopyranose) in aqueous solution. Comparison of the vacuum and solution free energy surfaces for maltose shows the principal effects of water to be an increase in the rotational freedom of the alpha(1 --> 4) linkage brought about by lowering the energy barrier for syn to anti conformational changes as well as expansion of the range of low-energy phi,psi conformations. This free energy analysis thus provides a thermodynamic and conformational rationale for the effects of water on alpha(1 --> 4)-linked polysaccharides and carbohydrate glasses.
Kuttel
Michelle M
MM
Department of Chemistry, University of Cape Town, Cape Town, South Africa.
Naidoo
Kevin J
KJ
D000465:Algorithms; D002241:Carbohydrates / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods*; D004187:Disaccharides / Q000737:chemistry; D006027:Glycosides / Q000737:chemistry; D008320:Maltose / Q000737:chemistry; D008962:Models, Theoretical; D008968:Molecular Conformation; D011134:Polysaccharides / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D002241:Carbohydrates; D004187:Disaccharides; D006027:Glycosides; D011134:Polysaccharides; D014867:Water; D008320:Maltose