Stabilization centers in various proteins

Interactions among residues together with their interactions with the surro unding medium determine the unique structure of globular proteins. An algor ithm was recently developed to locate residues participating in cooperative long-range interactions, called stabilization center residues, that are pr imarily responsible for preventing the decay of the 3D structure. While our statistical analysis showed that interactions of stabilization center resi dues hardly influence the formation of the various secondary structure elem ents, the distribution of the stabilization center residues is rather uneve n among the secondary structure elements. Here we analyzed the frequency an d distribution of the stabilization center residues and their interacting p airs in secondary structure classes to learn about the effect of secondary structure on the formation and properties of stabilization centers and abou t the types of interactions responsible for stabilization of proteins of va rious secondary structure classes. It was found that residues from the same secondary structure tend to interact with each other in the stabilization centers of all classes. It is also suggested that the folding-unfolding equ ilibrium is governed by different principles for class all-a than for the r est of the classes.