We demonstrate the use of crystals processed by a pulsed UV laser as seeds for protein crystallization. A hen-egg-white lysozyme crystal, which was successfully laser-processed without causing significant damage, was seeded and grown larger than its original size. Polarized light microscopy and X-ray diffraction analysis showed that the crystal grown by seeding was a single crystal of suitable quality for X-ray crystallography. The results support the effectiveness of UV-Iaser processing for protein crystals. Furthermore, this seeding technique, which we call laser-cut seeding, will be useful for the production of a seed of suitable size and shape in macroseeding, for the elimination of a damaged section-in a growing crystal, and for removing useless crystals from polycrystals.
