| Collagen monomers form a variety of aggregates in solution preferentially, depending upon the conditions to which they are subjected. Preferential aggregate morphology was influenced by modifying the surface charge of collagen monomer by reaction with methylglyoxal, resulting in both a decrease in fibrillar diameter and a change in surface characteristics as compared to the well characterized native collagen and shown by atomic force microscopy. By introducing the bulky, negatively charged alpha1-acid glycoprotein, fibrous long spacing collagen was produced, with a greater fibrillar diameter than native collagen, and surface morphology more like the methylglyoxal modified collagen fibrils. Upon addition of the zwitterionic ATP molecule to collagen, segmental long spacing collagen crystallites may be formed. By 31P-NMR, ATP was shown to be bound within the crystallite, probably through some sort of electrostatic interaction. All of these morphological influences have in common the interaction of charges and varying of steric constraints. |
