Femtosecond protein nanocrystallography-data analysis methods

• Published in: Optics express Vol. 18; no. 6; pp. 5713 - 5723
• Main Authors: Kirian, Richard A, Wang, Xiaoyu, Weierstall, Uwe, Schmidt, Kevin E, Spence, John C H, Hunter, Mark, Fromme, Petra, White, Thomas, Chapman, Henry N, Holton, James
• Format: Journal Article
• Language: English
• Published: United States 15.03.2010
• Subjects: Algorithms; Pattern Recognition, Automated - methods; Photosystem I Protein Complex - ultrastructure; X-Ray Diffraction - methods
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.18.005713

X-ray diffraction patterns may be obtained from individual submicron protein nanocrystals using a femtosecond pulse from a free-electron X-ray laser. Many "single-shot" patterns are read out every second from a stream of nanocrystals lying in random orientations. The short pulse terminates before significant atomic (or electronic) motion commences, minimizing radiation damage. Simulated patterns for Photosystem I nanocrystals are used to develop a method for recovering structure factors from tens of thousands of snapshot patterns from nanocrystals varying in size, shape and orientation. We determine the number of shots needed for a required accuracy in structure factor measurement and resolution, and investigate the convergence of our Monte-Carlo integration method.