Laser-Induced Crystallization of Standard Proteins on Ultra-Hydrophobic Surface and Characterization Using Raman Spectroscopy

Structural information helps to understand the function of the proteins and provides potential protein-ligand interactions of new drugs. X-ray crystallography is a powerful technique to determine the structure in three-dimensional geometry. However, obtaining high-quality single crystals remains an obstacle in macromolecular crystallography. Laser-induced crystallization is emerging as an alternative technique to circumvent this problem. In this study, we have prepared ultra-hydrophobic surfaces and used them for protein crystallization. Three model proteins, lysozyme, ferritin, and proteinase K, with distinct hydrophobicity, were used for this study. The protein droplet placed on three surfaces (non-siliconized, siliconized, and candle soot films) is exposed to a diode laser (785 nm, 75 mW). Ultra-hydrophobic candle soot surfaced coverslips rapidly yielded the crystals in conventional and laser-exposed droplets. Proteinase K nucleated faster than the lysozyme/ferritin on candle soot coated surface, compared to the regular coverslips suggesting that ultra-hydrophobic surfaces assisted laser-induced crystallization will play an essential role in protein crystallization.