ABSTRACT

This article mainly reviews our recent studies on mechanical properties of protein single crystals such as tetragonal hen egg-white lysozyme crystals. This also includes the growth of large single crystals by the solubility-gradient method and the characterization of crystal defects by X-ray topography. Using the large crystals, the sound velocities are measured by the ultrasonic pulse-echo method. The elastic constants are estimated from the measured sound velocity. The plastic deformation and Vickers micro-hardness are examined by the indentation method. It should be noticed that these mechanical properties strongly depend on the water in the crystals. Such mechanical properties of protein crystals are discussed in the light of the water-mediated intermolecular interaction in the crystals.