FR-X - Ultra High-Intensity Microfocus Rotating Anode X-Ray Generator

The FR-X was designed to be utilized in structural biology and material science, and provides the highest usable X-ray flux available for the laboratory researcher. The new design provides 20% more flux compared to the previous model and also a new direct-drive anode that reduces maintenance expenses considerably. The standard dual port design can be combined with an optional dual wavelength anode to provide the ultimate in experimental flexibility and end-station utilization.

The FR-X design is based on years of proven craftsmanship to provide outstanding instrument reliability. With a Rigaku X-ray source there is no need to take a chance that the X-ray source may fail to provide the needed up time and performance.

A key feature of the FR-X is the standard dual port configuration. Rigaku pioneered the use of multi-metal anode targets and the FR-X continues this tradition by offering optional dual banded anode targets. This helps in designing a multiple wavelength experiment where the sample can remain in place between switching of wavelengths. It also expands the capabilities of the experimental setup by increasing the types of samples that can be measured.

Key Features

The key features of the FR-X are:

  • Highest flux of any microfocus rotating anode X-ray generator
  • Direct drive rotating anode for lower maintenance expense
  • Screen crystals where no diffraction is seen using a conventional rotating anode or sealed tube source
  • Optional dual wavelength anodes with computer controlled wavelength selection
  • Choice of anode materials: Cu, Cr, Mo, Cu/Cr, Cu/Co
  • Smallest focal spot size of any rotating anode X-ray generator (70 µm diameter circle)
  • Small beam provides greater flux density and less background for small samples
  • Increases laboratory throughput by allowing for shorter exposure times and faster data collection
  • Collect full data sets on samples where only low-resolution reflections were seen on a standard system

Applications

The applications of FR-X are:

  • X-ray Diffraction (XRD)
  • Powder X-ray Diffraction (PXRD)
  • Small Angle X-ray Scattering (SAXS)
  • Single Wavelength Anomalous Dispersion (SAD) Phasing
  • Single Isomorphous Replacement with Anomalous Scattering (SIRAS) Phasing
  • Wide Angle X-ray Scattering (WAXS)
  • X-ray Reflectometry (XRR)
  • Protein Crystallography
  • Chemical Crystallography
  • Small Molecule Crystallography
  • Macromolecular Crystallography

 

Thaumatin

Using the VariMax HF optic FR-X and the PILATUS 200K, three scans were obtained on a 250 µm thaumatin crystal in just 4 minutes and 16 seconds.

Table 1. Data Collection Parameters

Scan # Distance ?start ? range ?? f ? 2? # img Exposure per image Total Exposure
1 70 mm -35° 70° 0.25° -108° 13° 280 0.2 sec 56 sec
2 70 mm -35° 70° 0.25° 72° 13° 280 0.2 sec 56 sec
3 70 mm -67° 170° 0.25° 72° 26° 23° 720 0.2 sec 2 min 24 sec

The HKL-3000R software was used to process the data set, which was complete to 1.69 Å with Rmerge and a low multiplicity. Employing 2.7 Å resolution, SHELXD identified 9 sulfurs (1 methionine and 8 disulfides) and these were later utilized in phasing to 1.8 Å with MLPHARE and SHELXE, and density modification to 1.69 Å with DM.

Using ARP/wARP, a model was designed within the experimental electron density map, and through quick and easy model refinement and adjustments with REFMAC, a thaumatin structure of Rfree = 17.7 % and R = 15.1% was produced.

Fo-Fc map (gray, 2.2 s) and anomalous difference map (magenta, 5 s).

Fo-Fc map (gray, 2.2 s) and anomalous difference map (magenta, 5 s).

Table 2. Scaling Statistics

Space group P41212
Unit cell lengths (Å)
angles (°)
57.9,57.9,149.8
90, 90, 90
Resolution (Å)
(last shell)
30-1.69
(1.72-1.69)
Completeness (%)
(last shell)
99.6
(96.5)
Multiplicity
(last shell)
6.8
(3.0)
<I>/<sI>
(last shell)
38.1
(6.9)
R-merge (%)
(last shell)
4.0
(15.0)

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