Improvements toward highly accurate diffraction experiments at the macromolecular micro-crystallography beamline BL-17A

Leonard M. G. Chavas,Yusuke Yamada,Noriyuki Igarashi,Masahiko Hiraki,Soichi Wakatsuki,Naohiro Matsugaki

doi:10.1107/s0909049513022875

Improvements toward highly accurate diffraction experiments at the macromolecular micro-crystallography beamline BL-17A

Leonard M. G. Chavas, Yusuke Yamada

Open Access

https://doi.org/10.1107/s0909049513022875

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Abstract

BL-17A is a macromolecular crystallography beamline dedicated to diffraction experiments conducted using micro-crystals and structure determination studies using a lower energy X-ray beam. In these experiments, highly accurate diffraction intensity measurements are definitively important. Since this beamline was constructed, the beamline apparatus has been improved in several ways to enable the collection of accurate diffraction data. The stability of the beam intensities at the sample position was recently improved by modifying the monochromator. The diffractometer has also been improved. A new detector table was installed to prevent distortions in the diffractometer's base during the repositioning of the diffractometer detector. A new pinhole system and an on-axis viewing system were installed to improve the X-ray beam profile at the sample position and the centering of tiny crystal samples.

Highlights

Macromolecular micro-crystallography has evolved rapidly and become a standard tool for macromolecular crystallography (Evans et al, 2011; Smith et al, 2012)
BL-17A is the first beamline dedicated to micro-crystal diffraction studies and structure determinations using a lower-energy X-ray beam (Igarashi et al, 2007)
The diffractometer at BL-17A was originally designed based on those developed at other macromolecular crystallography beamlines, BL-5A and AR-NW12A, at the Photon Factory

Summary

Introduction

Macromolecular micro-crystallography has evolved rapidly and become a standard tool for macromolecular crystallography (Evans et al, 2011; Smith et al, 2012). The Photon Factory includes five beamlines for macromolecular crystallography studies. BL-17A is the first beamline dedicated to micro-crystal diffraction studies and structure determinations using a lower-energy X-ray beam (Igarashi et al, 2007). Certain biological targets can be difficult to analyze, and the beamline performance requirements have increased over time. The sizes of crystals that users bring to the beamline are becoming smaller, necessitating more stable beams. The beamline must be improved to respond to these requirements (Igarashi et al, 2008). This article describes several recent improvements in the beamline instrumentation that enable highly accurate diffraction experiments at BL-17A

Beamline configuration

DCM improvements

A new detector table

A new collimator

On-axis viewing system

Summary