Miki Senda
High Energy Accelerator Research Organization (KEK), Japan
Title: A comprehensive strategy to obtain high quality crystals
Biography
Biography: Miki Senda
Abstract
Current X-ray sources of synchrotron radiation enable us to determine the crystal structures of proteins even if the crystals were diffracted only to medium or low resolution. However, high-resolution crystal structures are still required for the pharmaceutical and biochemical sciences. When obtained crystals were of poor quality and insufficient for crystal structure determination, post-crystallization treatment could improve the crystal quality. Our experiences of crystal structure analyses of histone chaperon TAF-Iβ, CagA oncoprotein from Helicobacter pylori and GTP sensor PI5P4Kβ showed that crystal soaking into cryoprotectants improved crystal-quality (1, 2, 3). Of the three proteins, crystal qualities of CagA and PI5P4Kβ were significantly improved by using more than one cryo-protectant. This method, multi-step soaking method, improved not only the maximum resolution but also success rate of high resolution data collection. Reproducibility of the crystallization is another critical problem in determining crystal structure. Anaerobic crystallization and immediate observation method are effective to improve the reproducibility of the crystallization. We would like to report some examples of the crystallization and crystal quality improvement by our strategy.
