Rapid localized crystallization of lysozyme by laser trapping

Area of Science:

• Biophysics
• Materials Science
• Crystallography

Background:

• Protein crystallization is crucial for structural biology and drug discovery.
• Controlling nucleation and crystal growth spatially and temporally remains a significant challenge.
• Spontaneous nucleation often leads to unpredictable crystal size, number, and quality.

Purpose of the Study:

• To develop a novel method for rapid and spatially controlled protein crystallization.
• To investigate the mechanism of laser-induced protein crystallization.
• To demonstrate the efficacy of laser trapping for hen egg-white lysozyme (HEWL) crystallization.

Main Methods:

• Utilizing a continuous-wave near-infrared laser beam tightly focused at the glass/solution interface.
• Employing a supersaturated buffer solution of hen egg-white lysozyme (HEWL).
• Initiating crystallization by stopping the laser irradiation after a 1-hour trapping period.

Main Results:

• Achieved millimetre-sized protein crystallization within 0.5 hours after laser cessation.
• Demonstrated excellent spatial and temporal controllability compared to spontaneous nucleation.
• Observed dense localization of HEWL crystals in a millimetre-sized circular area with specific optical axis orientations.

Conclusions:

• Laser trapping provides a highly effective method for controlled protein crystallization.
• A proposed mechanism involves nucleation and growth within laser-induced HEWL liquid-like clusters after irradiation.
• This technique offers significant advantages for producing high-quality protein crystals rapidly and controllably.