Ab Initio Based conformational study of the crystalline α‐chitin

Abstract

The equilibrium structure including the network of hydrogen bonds of an α-chitin crystal is determined combining density-functional theory (DFT), self-consistent DFT-based tight-binding (SCC-DFTB), and empirical forcefield molecular dynamics (MD) simulations. Based on the equilibrium geometry several possible crystal conformations (local energy minima) have been identified and related to hydrogen bond patterns. Our results provide new insight and allow to resolve the contradicting α-chitin structural models proposed by various experiments.

Poriferan Chitin as a Versatile Template for Extreme Biomimetics

“…As a result, the proposed structure contains two type of amide groups, which differ in their hydrogen bonding environments; explaining the splitting of the I amide band in the IR spectra of α-chitin. Although this α-chitin model proposed by Minke and Blackwell is commonly accepted, it still remains a topic of extensive of experimental [81,87] and theoretical ab initio studies [88]. These studies gave evidence of intermolecular hydrogen bonds in the G-G+ conformations [88] and formation of special hydrogen bond networks [81].…”

The structure and dynamics of chitin nanofibrils in an aqueous environment revealed by molecular dynamics simulations

“…Chitin-protein nanobrils further organize into stacks of planar arrays that form the so-called twisted plywood structure commonly found in all exoskeletal elements of Arthropoda. While the ground-state structure of a-chitin, 7,8,12,13 its mechanical properties and the impact on the overall mechanical performance of the composite cuticle have been extensively studied both theoretically and experimentally, 14,15 little is known about how it organizes to form the chitin-protein nanobrils. During the process of cuticle formation, 16 chitin molecules are produced by the membrane inserted enzyme chitin synthase.…”

Interactions Between Sodium Ion and Constituents of Chitosan: DFT Study

“…Glucosamine and acetylglucosamine molecules may exist in linear or cyclic forms; the latter being the most stable and favored form [1,28,29]. Different cyclic conformers have been identified [1,21].…”