Investigations on geometrical features in induced ordering of collagen by small molecules

Binding energies of the interaction of collagen like triple helical peptides with a series of polyphenols, viz. gallic acid, catechin, epigallocatechingallate and pentagalloylglucose have been computed using molecular modelling approaches. A correlation of calculated binding energies with the interfacial molecular volumes involved in the interaction is observed. Calculated interface surface areas for the binding of polyphenols with collagen-like triple helical peptides vary in the range of 60–210 Å2 and hydrogen bond lengths vary in the range of 2,7–3,4 Å . Interfacial molecular volumes can be calculated from the solvent inaccessible surface areas and hydrogen bond lengths involved in the binding of polyphenols to collagen. Molecular aggregation of collagen in the presence of some polyphenols and chromium (III) salts has been probed experimentally in monolayer systems. The monolayer arrangement of collagen seems to be influenced by the presence of small molecules like formaldehyde, gluteraldehyde, tannic acid and chromium (III) salts. A fractal structure is observed on account of two-dimensional aggregation of collagen induced by tanning species. Atomic force microscopy has been employed to probe the topographic images of two-dimensional aggregation of collagen induced by chromium (III) salts. A case is made that long-range ordering of collagen by molecular species involved in its stabilisation is influenced by molecular geometries involved in its interaction with small molecules.