Temperature Dependence and Anisotropic Effects in the Thermal Properties of Hen Egg-White Lysozyme Crystals

Syou Maki,Katsumasa Higo,Toshiaki Arata,Yuki Isaka,Eka Erzalia,Seiichi Tanaka,Mizuki Kato,Masayuki Hagiwara,Ryunosuke Maekawa,Seiji Fujiwara

doi:10.3390/sym12081279

Abstract

We measured the thermal conductivity (λ) and thermal diffusivity (α) of tetragonal hen egg-white lysozyme (HEWL) crystals by the transient short-hot wire method. The crystals were grown by two different methods: Magnetically levitated crystals were realized with a superconducting magnet, the c-axis of which was perpendicularly orientated in the direction of the wire, and naturally grown crystals realized by the two-liquid method, grown randomly. We confirmed the temperature dependence in both the λ and α properties by measuring the variations in temperature and by statistical analysis. These properties differed slightly depending on the presence or absence of a magnetic field applied during the crystal growth. We hypothesize that the difference originated from the orientation of the crystals caused by the magnetic field. The statistical analyses demonstrated the possibility that asymmetric thermal conduction in the protein crystals provides anisotropic effects of the thermal properties.

Highlights

Biophysical researchers know from experience that the appropriate temperature control is one of the most dominant factors in realizing high-quality protein crystals
The thermal conductivity and thermal diffusivity of tetragonal hen egg-white lysozyme (HEWL) crystals were measured by means of the transient short-hot wire method
The magnetically levitated crystals were realized by a superconducting magnet, the c-axis of which was perpendicularly orientated to the direction of the wire

Summary

Introduction

Biophysical researchers know from experience that the appropriate temperature control is one of the most dominant factors in realizing high-quality protein crystals. Thermophysical researchers are confident that the thermal control should be an approach in considering the crystallization process as a heat and mass transfer phenomena. We believe that the thermal properties of protein crystals would advance the understanding of crystal growth as a heat and mass transfer phenomena, and could provide guidance for engineered protein crystal applications. Most of the thermal properties of protein crystals have long remained unknown. This is attributed to various practical difficulties in the measurement of the crystals, which are characterized by smallness, fragility, and delicacy. A key to this success is that we jointly utilized

Results

Discussion

Conclusion