Development of a shutterless continuous rotation method using an X-ray CMOS detector for protein crystallography.

Kazuya Hasegawa,Seiki Baba,Masaki Yamamoto,Tetsuya Shimizu,Takashi Kumasaka,Takaaki Hikima,Kunio Hirata,Nobutaka Shimizu

doi:10.1107/s0021889809042277

Abstract

A new shutterless continuous rotation method using an X-ray complementary metal-oxide semiconductor (CMOS) detector has been developed for high-speed, precise data collection in protein crystallography. The principle of operation and the basic performance of the X-ray CMOS detector (Hamamatsu Photonics KK C10158DK) have been shown to be appropriate to the shutterless continuous rotation method. The data quality of the continuous rotation method is comparable to that of the conventional oscillation method using a CCD detector and, furthermore, the combination with fine ϕ slicing improves the data accuracy without increasing the data-collection time. The new method is more sensitive to diffraction intensity because of the narrow dynamic range of the CMOS detector. However, the strong diffraction spots were found to be precisely measured by recording them on successive multiple images by selecting an adequate rotation step. The new method has been used to successfully determine three protein structures by multi- and single-wavelength anomalous diffraction phasing and has thereby been proved applicable in protein crystallography. The apparatus and method may become a powerful tool at synchrotron protein crystallography beamlines with important potential across a wide range of X-ray wavelengths.

Highlights

The oscillation method with an X-ray CCD area detector has been widely used in the past decade or so at synchrotron beamlines for protein crystallography to collect diffraction data sets
The basic performance of the detector such as dark current, readout noise, linearity and non-uniformity was evaluated first, because this evaluation was necessary for diffraction image correction
Our results show that the continuous rotation method using the complementary metal-oxide semiconductor (CMOS) detector C10158DK can be successfully applied to collecting diffraction data at protein crystallography beamlines

Summary

Introduction

The oscillation method with an X-ray CCD area detector has been widely used in the past decade or so at synchrotron beamlines for protein crystallography to collect diffraction data sets. Snell et al (1995) probed the limits of how small the mosaicity could be for a protein crystal and thereby the S/N at the highest-resolution weak-reflection part of the diffraction pattern. They highlighted the importance of fine ’ slicing, because these weak reflections would be swamped with background if coarse ’ slicing was used.

Methods

Results

Discussion

Conclusion