Macromolecular Diffraction Biotechnology Resource

Macromolecular Diffraction Biotechnology Resource

Research Emphasis

Current Research

This resource, also known as MacCHESS, operates three insertion-device beamlines (stations A-1, F-1, and F-2) at the Cornell High Energy Synchrotron Source (CHESS) devoted to macromolecular crystallography. In addition, the resource supports additional bending magnet stations for part-time macromolecular X-ray experiments. The resource specializes in large unit-cell diffraction, ultra high-resolution diffraction, multiple-wavelength anomalous dispersion (MAD) phasing, rapid-throughput crystallography (structure-based drug design and structural genomics), microdiffraction, multiple-beam diffraction, and software development

Resource Capabilities

Methods

Unit cells as large as 1400 Å have been resolved. Diffraction to 0.72 Å has been collected. Structures as large as 370 kDa have been solved by MAD phasing. As many as 70 selenium atoms have been located from anomalous data. Datasets from ideal crystals can be collected in a few seconds. Typical exposure times vary from 5 to 120 seconds. The resource is sufficiently efficient to accommodate hundreds of researchers each year.

Instruments

All stations use charge-coupled device area detectors. Image plates are also available. Sample cryocoolers are available at the three wiggler stations. Station A-1 is for monochromatic measurements; a 49-pole wiggler replaces the 24-pole wiggler. Station F-1 is a monochromatic X-ray station designed to accommodate large unit-cell samples. The station is equipped with a biohazard containment facility rated at Biosafety Level 3. Station F-2 is a tunable facility designed for MAD phasing from which the X-ray energy can be tuned from 7.9 to 16 KeV. A cold room is present on site; microscopes are available at all stations. Three-dimensional graphics are available on some computers. Over a dozen Alpha computers support data processing.

Software

A data collection graphical user interface provides ease in collecting the diffraction data. All station hardware motors are controlled with simple software. X-ray diffraction data are analyzed using the DPS/Mosflm and DENZO software.