Low-temperature calorimetry of biological macromolecules

Abstract

This review shows the modern methods of calorimetry to be highly informative in studying the conformational properties of biopolymers when applied over a broad range of temperatures including the liquid-helium region, i.e., at temperatures far from the region of functioning of the macromolecules. Such an approach is typical in solving problems of the physics of the condensed state, since it allows one to reveal the characteristic features of a material by analyzing its physical properties under extreme external conditions of the environment (low and high temperatures, high pressures, etc.). This article collects and classifies the experimental data on the heat capacity of amino acids, peptides, polypeptides, proteins, and nucleic acids, and correlates them with the existing theories of the heat capacity of highly anisotropic structures at low temperatures. The observed low-temperature phase transitions in biopolymer-solvent systems are described, and the thermal properties of biopolymer chains are discussed in the light of the effect of the solvent and of dissolved ions of salts.