Molecular modelling of bacterial deep rough mutant lipopolysaccharide of Escherichia coli.

摘要: Molecular modelling techniques have been applied to compute the conformation accessible bacterial deep rough lipopolysaccharide of Escherichia coli (Re-LPS). Analyses results showed that models typically exhibit a tilt diglucosamine backbone with respect membrane normal 53 +/- 7 degrees while both glucosamine ring planes are oriented approximately parallel normal. Different were found show compact and elongated types acyl chain arrangements, producing anisotropic lateral dimensions 1.0-1.1 nm 1.7-2.0 for shorter longer side, respectively. The conformationally allowed range isolated dOclA(alpha-2-4)dOclA disaccharide (dOclA = 3-deoxy-D-mannooctulosonic acid) was be extremely limited. It appeared dOclA (dOclA)2 is centred at top Re-LPS molecule preferring two orientations stabilized by hydrogen bonds involving only one phosphate group lipid A moiety time. effect charges on conformations has studied in separate calculations. From these calculations it obvious no significant effects moieties. However, orientation part highly sensitive charges, i.e. charged proximity carboxyl groups prevented strong electrostatic repulsion between negatively groups. In order rationalize packing models, simple geometrical model which correlates energically favoured close chains proposed. Furthermore, possibility chelate-like complexation divalent cations its contribution head mobility discussed.