Crystallization of Lysozyme Based on Molecular Assembling by Photon Pressure

In this paper, we demonstrated a novel technique to promote crystallization of hen egg-white lysozyme in heavy water. The technique was essentially based on aggregation of the protein molecules by photon pressure generated under irradiation of a cw 1064 nm laser beam to the protein solution. When photon pressure was kept being exerted for 1–2 h on the sample solution, a small particle identified to the molecular aggregate of lysozyme was produced, as proved by in situ Raman microspectroscopy on the particle. Furthermore, we confirmed that aggregation of lysozyme by photon pressure led to crystallization of the protein.