Formation Sites and Microscopic Conformation Study on the Konjac Glucomannan Molecular Helices

In this work,the formation sites,helical parameters and hydrogen bond positions of Konjac glucomannan molecular helices were investigated using molecular dynamic simulation method.To our interest,the KGM chain is mainly composed by local left and right helix structures.The formation sites of KGM chain might locate at the chain-segments containing acetyl groups,and the left helix is the favorable conformation of KGM.Temperature-dependent molecule conformation study indicates that the right helix is dominant when the temperature is lower than 343 K,above which,however,the left helix is dominating (right helix disappears).In addition,intramolecular hydrogen bonds in the left helix can be found at the-OH groups on C(2),C(4) and C(6) of mannose residues;comparably,the intramolecular hydrogen bonds in the right helix can be mainly observed at the -OH groups on C(4) and C(6) of the mannose residues and C(3) of the glucose residues.In conclusion,molecular dynamic simulation is an efficient method for the microscopic conformation study of glucomannan molecular helices.