Heat conduction by thyroid hormone receptors

Thyroid hormone receptors (THRs) together with hormone binding and dissociation are important in gene expressions. The heat conduction properties such as heat capacity, thermal diffusivity and thermal conductivity of THR isoforms are determined by means of molecular dynamics simulations. Mean energy fluctuations in canonical ensemble at 310 K and theory of mole fraction are used to find the heat capacity of THRs in solution. The larger heat capacity of liganded THR-β than that of unliganded THR-β signifies the effect of receptor-ligand interactions, and hydrophobic, vibrational and conformational changes. The specific heats of THR isoforms in solution range from 2000 to 2200 Jkg⁻¹K⁻¹ at 310 K which lie within the experimental range for the native globular proteins. Providing temperature relaxation from 310 K to 200 K across protein-water interface in nano-droplets, the thermal diffusivity of THRs ranges from 1.28×10⁻⁷ to 1.57×10⁻⁷ m²/s which is around 1.46×10⁻⁷ m²/s for water. The thermal conductivity of THRs lies in the range 0.26–0.30 Wm⁻¹K⁻¹ which is about half the value, 0.64 Wm⁻¹K⁻¹ for water at 310 K.