In view of the inherently crowded nature of the intracellular milieu, most macromolecules are likely to be in physical contact with each other. Since all the components in a cell have evolved in parallel, they had ample opportunity to adapt to such environment (to the advantage of the organism) through molecular evolution. It is believed that confined macromolecules in each cell have reached mutual recognition for a better organization and coordinated function. ý
Cell biologists increasingly realize the importance of molecular recognition, and this topics is currently a favored subject of multidisciplinary research. Macromolecular recognition (as protein folding) is determined by the sequence, 3D structure and the environment. It is effected by building blocks occuring at the surface of macromolecules, being complementary in terms of:
Most these factors are predictable through computer analysis of known 3D structures or existing models of macromolecules suspected to interact and the simulation of their mutual docking. Other (wet) approaches to detect macromolecular interaction are non-denaturating separation methods (ultracentrifugation. gel exclusion or electrophoresis), or recombinant DNA methods (e.g., yeast double hybrid system).