5. November 2018

Publication-quality diffraction data from the University of Liverpool

The upgraded diffractometer in the Barkla lab in Liverpool complements XFEL beamtime for the study of pH-dependent conformational changes in nitride reductases. Samar Hasnain and Svetlana Antonyuk's groups collect close-to-synchrotron data with 24/7 beam availability.

 

Dr. Svetlana Antonyuk in front of the Barkla laboratory diffractometer

 

Easy and affordable upgrades to PILATUS3 and EIGER

Are you lucky enough to have a diffractometer equipped with a mardtb goniostat? Designed for synchrotron applications and famously dependable, many of these instruments have provided long years of reliable service in academic crystallography laboratories and the pharmaceutical industry. They continue to impress with advanced features like automatic beam alignment for maximum flux and crystal centering at the click of a button, and they enjoy full technical support. This is in some ways as close as you can get to a synchrotron in your laboratory.

 

The detectors installed on most mardtbs haven't fared quite as well. Image plates such as the venerable mar345 used to guarantee great data, but their slow readout prevents fine phi-slicing and limits the achievable data quality. CCD detectors require frequent maintenance and are so noisy that the weakest-diffracting crystals are often unmeasurable. Extremely long exposures will be dominated by detector noise.

 

An obsolete detector does not mean you have to mothball your diffractometer. marXperts, the company that continues to manufacture and support mardtb goniostats, has fully integrated the entire line of DECTRIS laboratory detectors for macromolecular crystallography. With a detector upgrade, you can now get most accurate data from the mardtb in your laboratory.

 

University of Liverpool – Excellent data 24/7

Prof. Samar Hasnain and Dr. Svetlana Antonyuk, co-directors of Barkla X-ray Laboratory of Biophysics at the University of Liverpool, have recently upgraded their diffractometer with an EIGER R 4M installed by marXperts. Students and postdocs are excited to use the new equipment and are collecting more data than before. "The EIGER R 4M is allowing us to collect good resolution data at home without waiting for synchrotron time”, says Antonyuk.

 

Hasnain and Antonyuk's Ph.D. student Thomas Halsted is equally enthusiastic. During his thesis work, he studied the enzymatic mechanism of copper nitrite reductases. Experiments done at SACLA, the X-ray free-electron laser in Japan, indicated two different nitrite binding modes. To understand what influences the binding, additional low-dose datasets were collected on the laboratory's diffractometer. Varying the pH value of the crystals helped to unambiguously establish a pH-dependent conformational change. Thanks to noise-free operation, the EIGER R 4M ensured highest signal to noise even at low dose. Halsted has just submitted for publication a paper describing his work and says, "My project wouldn't have been successful without the data collected in the laboratory."

 

Active site of Achromobacter cycloclastes nitrite reductase at pH 6. The two partially overlapping NO2 molecules (center) reflect a pH-dependent conformation change.

 

Maximize the value of your diffractometer

These are exciting times for crystallography laboratories. Technology that has revolutionized data collection at synchrotrons is now available in attractively priced products for laboratories. If you are operating a mardtb goniostat, marXperts can replace your slow image plate or noisy CCD with a state-of-the-art EIGER or PILATUS detector. Both the PILATUS3 R 1M and the EIGER R 4M offer a detective area that approaches that of image plates but will record sharper spots with better signal-to-noise ratios and allow for shutterless data collection. Your data quality will increase correspondingly.

 

Similarly, if you have an old detector on another goniostat, the most economical upgrade might be a new mardtb with a DECTRIS detector. marXperts will also upgrade your source to a MetalJet or a modern microfocus sealed tube if required. Either way, your diffractometer will become a more powerful tool for your science.