Fast, automated, continuous energy scans for experimental phasing at the BioMAX beamline.

Area of Science:

• Structural Biology
• Biophysics
• Materials Science

Background:

• X-ray macromolecular crystallography (MX) relies on experimental phasing techniques like single-wavelength anomalous dispersion (SAD) and multi-wavelength anomalous dispersion (MAD).
• Effective SAD and MAD experiments require reliable, rapid, and automated energy scan routines at synchrotron beamlines.
• Previous methods involved step scans, which were less efficient and increased sample exposure.

Purpose of the Study:

• To report the implementation of a novel continuous energy scan procedure at the BioMAX MX beamline.
• To improve the efficiency and automation of energy scans for anomalous dispersion experiments.
• To reduce X-ray exposure time for samples during data acquisition.

Main Methods:

• Development and implementation of a fully automated continuous energy scan routine.
• Measurement of accurate fluorescence counts across X-ray absorption edges.
• Comparison of the continuous scan with the previously used conventional step scan.

Main Results:

• The new continuous energy scan is approximately five times faster than the conventional step scan.
• The procedure is fully automated and minimizes sample exposure to X-rays.
• Accurate fluorescence counts are obtained over the absorption edge of interest.

Conclusions:

• The implemented continuous energy scan significantly enhances the speed and efficiency of data collection for MX experiments.
• This advancement facilitates prompt access to anomalous scattering data crucial for SAD and MAD phasing.
• The automated nature of the scan improves workflow and reduces experimental time at synchrotron facilities.