Do protein crystals nucleate within dense liquid clusters

摘要: Protein-dense liquid clusters are regions of high protein concentration that have been observed in solutions several proteins. The typical cluster size varies from tens to hundreds nanometres and their volume fraction remains below 10−3 the solution. According two-step mechanism nucleation, protein-rich serve as locations for precursors nucleation crystals. While explained unusual features crystal kinetics, a direct observation its validity crystals has lacking. Here, two independent observations with proteins lysozyme glucose isomerase discussed. Firstly, evolutions nucleating were characterized simultaneously by dynamic light scattering (DLS) confocal depolarized (cDDLS), respectively. It is demonstrated appear following significant delay after formation. cDDLS correlation functions follow Gaussian decay, indicative nondiffusive motion. A possible explanation contained inside large driven elasticity surface. Secondly, oblique illumination dark-field microscopy reveals evolution without newly nucleated grown freely diffusing Collectively, indicate nucleation.