Effects of Small Biomolecules on Lysozyme Crystallization

Abstract

To develop appropriate biocompatible nucleants, glutathione (GSH), glycine (Gly) and cysteine (Cys) were used as the biomolecular additives to study their effect on the regulation of lysozyme crystallization. Characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, circular dichroism, etc., the results show that GSH can effectively promote protein crystallization under even lower concentrations of lysozyme by enhancing the nucleation rate, comparing with the additives of Gly and Cys, whereas lysozyme crystal structures produced in the presence of the biomolecular additives are similar to those in the absence of the additives. It shows in combination with molecular modeling that the stronger interactions between small biomolecular additives and the lysozyme LOOP accelerate the heterogeneous nucleation. It is suggested that such small biomolecules can be used as promising nucleants for promoting protein crystallization in the food and pharmaceutical industries.