Protein Crystallography

Single crystals of macromolecules and proteins are usually very small and show only poor diffraction thus making the determination of such crystal structures a challenging task. In general, the interaction of electromagnetic radiation with matter increases with the wavelength approximately by the power of three. The use of Cu-K_α radiation, therefore, results in a more efficient diffraction — compared to e.g. Mo-K_α or Ag-K_α — and usually leads to a reasonable atomic and spatial resolution of the diffraction pattern. This is indispensable in particular for crystal structures with long cell axes.

Protein Crystallography with IµS-Cu MX

The Cu-IµS MX is the brightest microfocus sealed tube for X-ray diffraction currently available. It delivers a two-dimensional focused beam with an unprecedented flux density of > 2.0 x 10¹⁰ phts/s/mm² Cu-K_α radiation giving a performance beyond traditional 5 kW rotating anode systems with second generation multilayer mirrors, such as Montel 200 or Osmic Blue mirrors. The high intensity and the excellent beam stability guarantees high data quality for applications such as crystal screening and S-SAD phasing. The beam cross-section of the image focus is about 0.11 mm (FWHM). The dedicated and patented mirror housing allows easy and reliable alignment. An optional variable aperture at the exit of the housing enables the reduction of the beam divergence in order to resolve long unit cell axes. The Cu-IµS MX is a reliable and easy-to-use X-ray source for compact, but powerful solutions in structural biology.

Now our latest IµS DIAMOND source exploits the extreme conductivity of diamond to achieve intensities of up to 6 x 10¹⁰ phts/s/mm², exceed the intensity of most rotating anodes sources.