title: Elastic constants in orthorhombic hen egg-white lysozyme crystals.
abstract: The ultrasonic sound velocities of cross-linked orthorhombic hen egg-white lysozyme (HEWL) crystals, including a large amount of water in the crystal, were measured using an ultrasonic pulse-echo method. As a result, seven elastic constants of orthorhombic crystals were observed to be C11 = 5.24 GPa, C22 = 4.87 GPa, C12 = 4.02 GPa, C33 = 5.23 GPa, C44 = 0.30 GPa, C55 = 0.40 GPa, and C66 = 0.43 GPa, respectively. However, C13 and C23 could not be observed because the suitable crystal planes could not be cut from bulk crystals. We conclude that the observed elastic constants of the cross-linked crystals are coincident with those of the intrinsic crystals without cross-linking. Moreover, the characteristics of the elastic constants in orthorhombic HEWL crystals are due to the fact that the shear elastic constants, C44, C55, and C66, are softer than in tetragonal crystals. That is, the shear components, C44, C55, and C66, are one half of those of the tetragonal crystals.
authors.affiliation: Citizen Holdings Company, Ltd, 840, Shimotomi, Tokorozawa, Saitama 359-8511, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kitajima
authors.affiliation: Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tsukashima
authors.affiliation: Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Fujii
authors.affiliation: Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tachibana
authors.affiliation: Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Koizumi
authors.affiliation: Department of Education, Yokohama Soei University, 1 Miho-cho, Midori-ku Yokohama 226-0015, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Wako
authors.affiliation: Department of Education, Yokohama Soei University, 1 Miho-cho, Midori-ku Yokohama 226-0015, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kojima
mesh_terms: D003198:Computer Simulation; D003460:Crystallization; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques; D006244:Hardness; D008956:Models, Chemical; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry* / Q000648:ultrastructure*; D011487:Protein Conformation; D033081:Shear Strength; D013314:Stress, Mechanical
chemical_list: C421864:hen egg lysozyme; D009113:Muramidase