Characterization of protein and virus crystals by quasi-planar wave X-ray topography: a comparison between crystals grown in solution and in agarose gel

Quasi-planar wave reflection profile and X-ray topography studies have been done to characterize the mosaicity of solution- and gel-grown crystals of three proteins, turkey egg-white (TEW) lysozyme, thaumatin, and a bacterial aspartyl-tRNA synthetase (AspRS) as well as of one virus, tomato bushy stu nt virus (TBSV). These materials are representative of a large range of mol ecular weight, overall particle shapes, crystals habits, packings, and solv ent contents. Measurements of the full-width at half-maximum (FWHM) of refl ections show that these different crystals have all a weak mosaicity. Topog raphs display the same features as those of the well-studied hen egg-white (HEW) lysozyme crystals: misorientation generated at the seed level for TEW lysozyme or thaumatin crystals and/or strains at growth sector boundaries for AspRS crystals. No growth defects are evidenced for TBSV crystals. For the study of crystals diffracting at lower resolution (AspRS and virus), a less absorbant sample holder, which facilitates crystal positioning in the X-ray beam, has been developed. The results obtained for solution- and gel- grown crystals do not show important differences. However, for TEW lysozyme and thaumatin crystals, one notices a larger dispersion of results in the solution case and an overall tendency for improved reproducibility of quali ty for gel-grown crystals. (C) 1999 Elsevier Science B.V. All rights reserv ed.