PXI - X06SA: Macromolecular Crystallography

PX Bild.png

X06SA (PXI) is the first macromolecular crystallography beamline at the Swiss Light Source. It is equipped with a flexible two-stage focusing X-ray optics system and a single–photon counting hybrid pixel area EIGER 16M (Dectris) detector. X06SA is well suited for micro-crystals, crystallography of large unit cell structures, and single/multiwavelength anomalous diffraction experiments (SAD/MAD).

Beamline Characteristics

Wavelength range (Å) 0.7 - 2.2
Spectral range (keV) 5.7 - 17.5
Energy resolution (%) 0.02
Flux at 12.4 keV at 400mA (ph/s) > 2 x 1012
Spot size h x v (μm) Fast change from 5 x 5 to 100 x 100, option to focus on detector
Smallest focusing 10 x 1. Smallest beam 2 x 1 is available upon request
Detector EIGER 16M X (133 Hz)

Beamline Features

Variable X-ray beam size, divergence, and focusing position

Control of beam size and divergence with a two-stage focusing X-ray optics and a movable secondary source position.
  • Standard micro-focus 5 x 5 μm2 to 100 x 100 μm2 (user friendly one button control)
  • Focus on detector (user friendly one button control)
  • Micron-size beam, 2 x 1 μm2 (upon request)

EIGER 16M: the most powerful X-ray detector for synchrotron application

75 x 75 μm2 pixel size, 3.8 μs dead time, 133 Hz frame rate, maximum count rate 5x108 phs/s/mm2
  • High sensibility with single photon counting and zero point-spread
  • High spacial resolution to high diffraction resolution with smaller pixel
  • Ultrafine-phi slicing with > 99% duty cycle, i.e. < 1% "non-recorded" photons
Left: one pixel resolution; right: high resolving power (1070 Å cell aixs)
Ultrafine-phi slicing

Continuous grid scan (up to 60 Hz)

  • Diffraction-based alignment
  • Fast grid-scan with micro-beam (micro-rastering)
  • Wojdyla et al., J. Appl. Cryst. 49, 944 (2016) DOI:10.1107/S1600576716006233
SLS goniometer and scanning motions
64 sec grid scan with 10 x 10 μm2 beam on a whole LCP bolus (400 x 400 μm2)
One-micron beam grid scan (micro-rastering)

IMISX serial crystallography for membrane and soluble protein

  • Eliminate the technically demanding and inefficient crystal-harvesting process in meso
  • Harvest, freeze, store and transport IMISX wells in standard cryo pin, vial, puck and dewar
  • Visualize micro-crystals in meso in cryo
  • Huang et al. Acta Cryst. D71, 1238 (2015) DOI:10.1107/S1399004715005210; Acta Cryst. D72, 93 (2016) 10.1107/S2059798315021683
IMISX at room temperature
IMISX at cryogenic temperature
On-axis microscope view of crystals in IMISXcryo wells under cryojet at beamline

Serial synchrotron crystallography (SSX) software suite at PXI and PXII

  • identification of well diffracting crystals with fast grid scan in DA+ GUI
  • evaluation of grid scan results and automated collection of multiple minisets performed in the CY+ GUI
  • automatic data processing (adp) of individual minisets
  • automatic data merging (adm) of multiple minisets using the sxdm package
  • automatic display of adp and adm results for the on-the- fly inspection (adp-tracker) and storage in the database (mxdb)
  • Basu et al., J. Synchrotron Radiat., 2019, 26(1):244-252 DOI:http://doi.org/10.1107/S1600577518016570

The CY+ GUI with results of the grid scan heat map.

The adp-tracker ‘SX-View’ mode, with the adm merging results for 100 PepTSt crystals displayed.

TELL sample changer

  • 20 seconds sample exchange time
  • dry mounting, standard 18 mm SPINE pins
  • Unipucks, NO SPINE pucks at 6S for use with TELL!!!
  • dewar capacity: 30 Unipucks

SLS PX software

  • easy and intuitive data acquisition with DA+ GUI
  • robust DA+ data acquisition engine (DA+ server and Escape)
  • SLS MX MonogDB database (so-called mxdb)
  • automated data processing (adp) pipelines for single data set, multi-orientation data sets and serial crystallography data
  • automated data merging (adm) for serial crystallography data with in-house sxdm pipeline
  • Wojdyla et al., J. Synchr. Rad. 25, 293 (2018) DOI:10.1107/S1600577517014503
Schematic of SLS automatic data analysis