I Dementieva | PubMed Health

PubMed1999

Taking MAD to the extreme: ultrafast protein structure determination.

Multiwavelength anomalous diffraction data were measured in 23 min from a 16 kDa selenomethionyl substituted protein, producing experimental phases to 2.25 A resolution. The data were collected on a mosaic 3 x 3 charge-coupled device using undulator radiation from the Structural Biology Center 19ID beamline at the Argonne National Laboratory's Advanced Photon Source. The phases were independently obtained semiautomatically by two crystallographic program suites, CCP4 and CNS. The quality and speed of this data acquisition exemplify the opportunities at third-generation synchrotron sources for high-throughput protein crystal structure determination.

Base Sequence↗

PubMed1999

MAD data collection - current trends.

The multiwavelength anomalous dispersion (MAD) method of protein structure determination is becoming a routine technique in protein crystallography. The increased number of wavelength-tuneable synchrotron beamlines capable of performing challenging MAD experiments, coupled with the widespread availability of charge-coupled device (CCD) based X-ray detectors with fast read-out times have brought MAD structure determination to a new exciting level. Ultrafast MAD data collection is now possible and, with the widespread use of selenium in the form of selenomethionine for phase determination, the method is growing in popularity. Recent developments in crystallographic software are complementing the above advances, paving the way for rapid protein structure determination. An overview of a typical MAD experiment is described, with emphasis on the rates and quality of data acquisition now achievable at third-generation synchrotron sources.

Chaperonins↗