ALL-ATOM MOLECULAR MODELING AND DYNAMICS SIMULATION OF TROPOCOLLAGEN STRUCTURES WITH CROSS-LINKING

概要

Collagen is the most abundant protein in humans and animals, and it is currently being applied to the development of novel materials used in medical devices. In order to improve the performance and usability of such devices, understanding the strength of collagen is key. The basic structural unit of collagen is tropocollagen (TC), which are nanometer-sized rods composed of characteristic triple helices of peptide molecules. As TC is too small to be evaluated experimentally, computer modeling and simulation using molecular dynamics (MD) are effective in its study. There are numerous cross-linked structures between TC molecules that are considered to have major effects on its mechanical properties, including strength and ductility. In this study, an all-atom model for MD computation is constructed in which three TC molecules are arranged in parallel together with some improvised cross- linking (CL) molecules. A simulation of the tensile test is conducted by pulling one of the molecules using the steered molecular dynamics (SMD) method in order to investigate the influence of CL molecules in the deformation process of TC molecules. The results revealed that the model with CL molecules requires greater load than the model without CL molecules until the TC molecules are removed. This study demonstrates that CL molecules play a major but microscopic role in increasing the strength of collagen.

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