Synchrotron Protein Crystallography

Among the Graphical User Interfaces (GUIs) demonstrated at the workshop at Brookhaven, was one developed for structural biologists using the Biology Dept-sponsored NSLS beam line X12-C. It is demonstrated here by (sitting, from left) K. Feng-Berman, NSLS Dept, and J. Skinner, BNL Biology. Looking on are (standing, from left) workshop co-sponsors B. Sweet, Biology, and S. Ealick, Cornell U.; and J. Pflugrath, Molecular Structure Corp., who helped Sweet, Skinner and Feng-Berman develop the GUI through a program coordinated by the Argonne National Lab Structural Biology Center. (Photo courtesy of R. Sweet.)

Under the auspices of the American Crystallographic Association's Committee on Apparatus and Standards and its Synchrotron Radiation Special Interest Group, a workshop on Graphical User Interfaces for Synchrotron Protein Crystallography was held at Brookhaven National Lab. March 19-21 1995. Synchrotron Radiation has become an important tool for protein and virus crystallographers. While the X-ray beams are getting hotter and the equipment to use them is becoming more complicated, potential users of these facilities are becoming both more numerous and less experienced in experimental crystallography. There is a tremendous need to make the user interface to these facilities as easy to use as possible.

An imponant component of the total user interface is the software that controls the data-collection process. Most operators of these facilities are constructing graphical user interfaces (GUIs) to this software. The chief motive for this is to assure first the quality and then the quantity of the data that are produced. This can be achieved only when the experimenter is able to manage the measurements and to assess the merit of the results in ways he can understand and control. Graphical computer interfaces provide a tool to make this control as convenient to use and easy to understand as possible.

The two-day workshop included a lecture on industry-wide standards for GUIs from a GUI theorist, lecture/demonstrations displaying GUI's that have been written or are under construction, descriptions of how beam line control, data acquisition and data reduction can be integrated to provide control and reliability, and working groups to discuss image-file formats, software for beamline-control, and standards for data-acquisition software. Experiment and beam line are currently under partially integrated GUI control at Brookhaven, and Daresbury has a new GUI controller for data collection.

Commercial products described at the meeting include Cirius2 from Molecular Simulations, MAR Research and ASDC and DENZO. Common tools have been developed at APS and ESRF. The Working Groups concluded that there should be a self-defining image file format with a header (in ASCII) that completely defines the experiment. then defines the format of the image data that follow. For beamline control, there should be essentially two buttons: [Align the beamline] and [Set the wavelength]. This group also identified a need for general-purpose software to allow communication among processes. Data-acquisition software should look and feel the same at each synchrotron, but there is unlikely to be a precise standard. Instead, there will be lots of home-brewed packages.

A complete set of notes from the workshop, including some graphics, can be viewed or retrieved from the WWW site for the BNL Structural Biology Beamline X12-C at: http://grx2.bio.bnl.gov/x12c/x12cinfo.html.