Principles of Protein Structure - H. Schulz 1982

Mechanisms of polypeptide chain folding and association
Aggregates of globular proteins

There are no fundamental differences between the aggregation of Structural domains and the aggregation of Globular Proteins.

The distinction between the association of structural domains within a single chain and the association of globular proteins (i.e., separate chains) is rather blurred. For instance, in rhodanese (Fig. 5.17, a), the domains of a single chain aggregate to form a highly symmetrical system [257], much like the subunits of a dimeric protein. During the assembly of the capsids of poliovirus [163] and Semliki Forest virus [258], A large number of protein globules are initially formed from a single polypeptide chain and are subsequently cleaved by a protease. Following Cleavage, the protein symmetrically aggregates to form the viral shell. This demonstrates that individual domains of a multidomain globular protein can be stable on their own and can also function as independent globular proteins. In general, however, the subunits of large protein aggregates are synthesized and folded separately.

There are numerous causes for aggregation. Among the diverse Functions facilitated by aggregation, the following can be highlighted: (1) the creation of complex multifunctional machinery; (2) the colocalization of Enzymes within a metabolic pathway to prevent the loss of metabolic intermediates; (3) the construction of structures with specific geometries, such as elongated channels; (4) the reduction of osmotic pressure; or (5) the expansion of potential manifestations of enzymatic activity, and consequently, The Emergence of novel regulatory mechanisms.