Macromolecular and nanoscale investigation of intermolecular interactions driving the self-assembly of collagen

Abstract

Collagens have remarkable ability to self-assemble into ordered fibrils. Assembly of collagens on 2-dimensional surfaces serves as a model system to study the dynamics of assembly process and the resulting fibrilar structure has potential biotechnological and biomedical applications. However, intermolecular forces driving the self-assembly of collagen are not well understood. Here, we apply the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to investigate the interactions between collagens and between collagen and the mica surface. Interactions are found to be attractive at all distances, which is consistent with literature. To further investigate the sequence-dependent organization of collagen molecules, we examined interaction near contact distances when collagen molecules are staggered to different degrees. We compared electrostatic, hydrophobic, and polar hydration interaction, and found that hydrophilic interaction plays a significant role on the molecular assembly by protecting the molecule from random collapse with a consistent repulsion barrier. Electrostatic interaction, on the other hand, exhibits local energy maxima and minima on D-periodic arrangements throughout the molecule leading to an oscillation effect on the axial self-assembly. Our approaches, in both macromolecular and nanoscale, provide insights into the factors that determine interactions among collagens and between collagen and mica.