Not so long ago, structural proteomics research was divided into two distinct campsx-ray crystallography and NMR spectroscopy. X-ray crystallography remains the gold standard for structural determination, but NMR capabilities are proving their value for proteins that can't be crystallized and in screening work.
For x-ray crystallography, there are two major optionsget the sample to a synchrotron beam line or conduct the work in one's own lab. For individual lab equipment, the trends are toward robustness and automation.
Stand-alone lab systems, like the MicroStar-H rotating anode generator from Bruker AXS (www.bruker-axs.com), let researchers perform much or all of the crystallography work that previously required traveling to a synchrotron beam line facility in their own labs, saving time and money.
"The MicroStar-H delivers x-ray intensities comparable to those of a second-generation synchrotron generator," according to Roger Durst, Ph.D., CTO, which is an order-of-magnitude increase when compared to previous models.
That increase in sensitivity lets users solve structures in their own labs and actually provides greater stability, albeit less brightness, than the strong synchrotron beam, which fluctuates. Another advantage, Dr. Durst says, is that the MicroStar-H can solve structures using native protein.
Selenomethionine is not required, "which is a big advantage," he says, so researchers can determine the location of sulfur atoms in the structure directly by using single wavelength anomalous diffraction (SAD).
Bruker also launched a new, high-sensitivity detector called Platinum, which regulates the x-ray spectra diffraction path. Readout time for a complete set of data is one second100 times faster than an image plate detector. It is more sensitive than an image plate detector by "about a factor of eight," Dr. Durst says.
In terms of efficiency, "charged-coupled devices like the Platinum have a significant advantage" in that they better detect the data at the outer edge of the image, by an order of magnitude.
In April, Bruker AXS opened its X-Ray Life Sciences Laboratory for protein crystallization and macromolecular structure determination in Delft, The Netherlands. "If you can't get a selenomat version of your protein, use ours to run a native SAD structure," Dr. Durst offers.