Conceptual design of novel IP-conveyor-belt Weissenberg mode data collection system with multi readers for macro-molecular crystallography. A comparison between Galaxy and Super Galaxy

Abstract

Galaxy is a Weissenberg type, high speed, high-resolution and highly accurate fully automatic data collection system using two cylindrical IP-cassettes each with a radius of 400mm and a width of 450mm. It was originally developed for static three-dimensional analysis using X-ray diffraction and was installed on bending magnet beamline BL6C at the Photon Factory. It was found, however, that Galaxy was also very useful for time-resolved protein crystallography on a time scale of minutes. This has prompted us to design a new IP-conveyor-belt Weissenberg-mode data collection system called Super Galaxy for time-resolved crystallography with improved time and crystallographic resolution over that achievable with Galaxy. Super Galaxy was designed with a half-cylinder shaped cassette with a radius of 420mm and a width of 690mm. Using 1.0Å incident X-rays, these dimensions correspond to a maximum resolutions of 0.71 Å in the vertical direction and 1.58Å in the horizontal. Upper and lower screens can be used to set the frame size of the recorded image. This function is useful not only to reduce the frame exchange time but also to save disk space on the data server. The use of an IP-conveyor-belt and many IP-readers make Super Galaxy well suited for time resolved, monochromatic X-ray crystallography at a very intense third generation SR beamline. Here we describe Galaxy and a conceptual design for Super Galaxy and compare their suitability for use as data collection systems for macromolecular time-resolved monochromatic X-ray crystallography.