INCORPORATION OF MICROCRYSTALS BY GROWING PROTEIN AND VIRUS CRYSTALS

In the course of time-lapse video and atomic force microscopy (AFM) in vestigations of macromolecular crystal growth, we frequently observed the sedimentation of microcrystals and three-dimensional nuclei onto t he surfaces of much larger, growing protein or virus crystals, This wa s followed by the direct incorporation over time of the smaller crysta ls into the bulk of the larger crystals, In some cases, clear indicati ons were present that upon absorption of the small crystal onto the su rface of the larger, there was proper alignment of the respective latt ices, and consolidation proceeded without observable defect formation, i,e,, the two lattices knitted together without discontinuity, In the case of at least one virus crystal, cubic satellite tobacco mosaic vi rus (STMV), addition of three-dimensional nuclei and subsequent expans ion provided the principal growth mechanism at high supersaturation, T his process has not been reported for growth from solution of conventi onal crystals, In numerous other instances, the lattices of the small and larger crystals were obviously misaligned, and incorporation occur red with the formation of some defect, This phenomenon of small crysta ls physically embedded in larger crystals could only degrade the overa ll diffraction and materials properties of macromolecular crystals. (C ) 1996 Wiley-Liss, Inc.