Stability of multi-subunit proteins and conformational lock

Abstract

One of the important physicochemical features of the proteins specifically multi-subunit types is their stability at high temperatures. The kinetics of the dissociation and denaturation of proteins possessing at least two subunits has certain challenges because the overall mechanism of dissociation can include hidden reversible and/or irreversible steps (conformational lock). There are numerous proteins related to diseases which are in equilibrium with oligomer forms. This equilibrium plays an important role in holding the activity levels of these proteins in vitro and in vivo. The stability of proteins is an essential milestone to study conformational changes of the proteins in the living cell. This concept is of great importance when proteins are used in biomedicine fields. The quaternary structure of multi-subunit proteins includes properties that affect function and kinetics of denaturation. The kinetics of denaturation may include some hidden stages of conformational transitions in the protein and steps of reversible dissociation of the oligomer. The transforming factors affect different areas especially active centers in the clefts of each subunit. The distinctive agent among all, is the temperature which sequentially destructs independent inter-subunit contact sites. Recent experimental data regarding dissociative mechanism for irreversible thermal denaturation of multi-subunit proteins have been summarized in the present paper.

Keywords: Conformational lock; Multi-subunit proteins; Residual activity; Thermal dissociation; Thermal inactivation.