Experience with commercial area detectors: a `buyer's' perspective

Area detectors have revolutionized data collection in protein crystallography, but unsubstantiated opinion as to the merits of these detectors has sometimes interfered with objective comparisons of area detector quality. Area detectors from four manufacturers were evaluated by collecting data sets on two different protein crystals, carboxypeptidase A and recombinant sperm whale myoglobin. These data sets were first compared by studying their internal consistency using R_sym measurements and as expected these R_sym values were excellent. Next, the data were studied by merging with diffractometer data sets and with each other. Finally, the myoglobin data were used to calculate anomalous difference Pattersons. Area detectors studied in this way included the Mark II from San Diego Multiwire Systems, the FAST from Enraf-Nonius, Inc., the R-AXIS II from Rigaku Corporation and the X-1000A from Siemens Analytical X-ray Instruments, Inc. Wide variations existed in the data-collection parameters chosen by the manufacturers, but all four detectors produced acceptable data as evidenced by mutual agreement and clear interpretability of anomalous difference Patterson maps based on the Fe atom in myoglobin.