REINFORCED PROTEIN CRYSTALS

Large tetragonal hen egg white lysozyme single crystals (up to 16 mm(3 )) can be obtained by the counter-diffusion method, using high concent ration silica gels. The protein crystal lattice is able to incorporate large amounts of silica while still maintaining its short-range cryst allographic order. The crystal morphology is controlled by the concent ration of the silica gel, which can reduce surface energy anisotropy t o such an extent that Spherical single crystals can be obtained as gro wth forms. The mechanical properties and the stability of the crystals against dehydration are improved by the incorporated hydrophilic sili ca polymeric network. This makes it possible to record full diffractio n data sets with a resolution better than 1.5 Angstrom from crystals g lued to glass fibers. Such reinforcement of the crystals facilitates t heir handling at ambient conditions and opens new possibilities for th e measurement of physical properties of large biological macromolecule s as well as for their technological applications. (C) 1998 Elsevier S ciertce Ltd.