Crystallography Endstation

Structure of the month:
Crystal structure of the Bacillus subtilis
Smc Joint domain (PDB entry: 5NMO,
published in Mol. Cell.).

 

The crystallography experiment at P11 provides high photon flux and microfocus capability (more details can be found here). A sample changing robot allows high-throughput crystallography and fast crystal screening. Crystals can be mounted in less than 10 s using an automatic sample changer (check the Sample Changer section for more details).

The crystallography endstation at P11 (Figure 1) is equipped with a high precision single axis goniometer with a combined sphere of confusion of smaller than 100 nm (Figure 2). The instrument provides an on-axis viewing system for easy crystal centering and beam alignment. The photon flux at the sample position can be measured with a 100 µm thick photo diode.

Figure 1: P11 crystallography endstation overview.

Figure 2: Detailed view of P11 crystallography experiment with goniometer.

Due to the very small divergence of the X-ray beam it is possible to measure unit cell sizes of up to 1500 Å at P11 (Figure 3). The energy can be freely chosen between 5.5 and 30 keV. A CVD diamond based X-ray feedback system provides a long term positional beam stability of better than 1 µm. The beamline is equipped with a Pilatus 6M fast detector which allows data collection with frame rates of up to 25 Hz.

In addition to the standard data collection features the beamline control software at P11 (Figure 4) provides a grid scan capability for crystal centering and measurement of micro crystals (with and without crystal rotation), auto processing of the data with XDS and an interface for serial crystallography.

Figure 3: Diffraction pattern of a protein with a 1300 Å cell axis (kindly provided from O. Daumke, Max Delbrück Center for Molecular Medicine Berlin).

Figure 4: P11 crystallography data collection GUI.