[Dynamic structure of globular proteins: conformational rigidity and fluctuational motility].
The data on medium-scale fluctuation of globular proteins revealed by hydrogen exchange, proteolytic degradation and 1H NMR are considered. It is shown that the main features of those conformational transitions including their cooperativity can be described within the model that is based on mobile equilibrium defects of a solid characterized by the integrity of properties of the polymeric monocrystal and the molecular organic crystal. The extent of the fluctuational motility of the protein structure is regulated by strain energy. The functional isomerization of the protein is realized as generalized collective fluctuation induced by destabilization of the structure. The hydration of the backbone may play an important role providing the conformational rigidity of the protein, the extent of hydration being varied upon temperature changes and in the presence of organic co-solvents. Unlike the solid, the liquid-like state of the protein globula is characterized by high fluctuational motility and very narrow distribution of probabilities of medium-scale fluctuations.
D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008961:Models, Structural; D011487:Protein Conformation; D011506:Proteins / Q000378:metabolism*
D011506:Proteins
Dinamicheskaia struktura globuliarnykh belkov: konformatsionnaia zhestkost' i fluktuatsionnaia podvizhnost'.