title: Upgrade of MacCHESS facility for X-ray scattering of biological macromolecules in solution.
abstract: X-ray scattering of biological macromolecules in solution is an increasingly popular tool for structural biology and benefits greatly from modern high-brightness synchrotron sources. The upgraded MacCHESS BioSAXS station is now located at the 49-pole wiggler beamline G1. The 20-fold improved flux over the previous beamline F2 provides higher sample throughput and autonomous X-ray scattering data collection using a unique SAXS/WAXS dual detectors configuration. This setup achieves a combined q-range from 0.007 to 0.7 Å(-1), enabling better characterization of smaller molecules, while opening opportunities for emerging wide-angle scattering methods. In addition, a facility upgrade of the positron storage ring to continuous top-up mode has improved beam stability and eliminated beam drift over the course of typical BioSAXS experiments. Single exposure times have been reduced to 2 s for 3.560 mg ml(-1) lysozyme with an average quality factor I/σ of 20 in the Guinier region. A novel disposable plastic sample cell design that incorporates lower background X-ray window material provides users with a more pristine sample environment than previously available. Systematic comparisons of common X-ray window materials bonded to the cell have also been extended to the wide-angle regime, offering new insight into best choices for various q-space ranges. In addition, a quantitative assessment of signal-to-noise levels has been performed on the station to allow users to estimate necessary exposure times for obtaining usable signals in the Guinier regime. Users also have access to a new BioSAXS sample preparation laboratory which houses essential wet-chemistry equipment and biophysical instrumentation. User experiments at the upgraded BioSAXS station have been on-going since commissioning of the beamline in Summer 2013. A planned upgrade of the G1 insertion device to an undulator for the Winter 2014 cycle is expected to further improve flux by an order of magnitude.
authors.affiliation: Macromolecular Diffraction Facility of the Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, 161 Synchrotron Drive, Ithaca, NY 14853, USA.
authors.forename: Alvin Samuel
authors.initials: AS
authors.lastname: Acerbo
authors.affiliation: Macromolecular Diffraction Facility of the Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, 161 Synchrotron Drive, Ithaca, NY 14853, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Cook
authors.affiliation: Macromolecular Diffraction Facility of the Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, 161 Synchrotron Drive, Ithaca, NY 14853, USA.
authors.forename: Richard Edward
authors.initials: RE
authors.lastname: Gillilan
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000737:chemistry; D000818:Animals; D003201:Computers; D003299:Cooperative Behavior; D004867:Equipment Design; D005568:Forms and Records Control; D015394:Molecular Structure; D009113:Muramidase / Q000737:chemistry; D009518:New York; D012371:Robotics; D053838:Scattering, Small Angle; D012984:Software; D012996:Solutions; D013048:Specimen Handling; D017356:Synchrotrons / Q000295:instrumentation*; D013696:Temperature; D014961:X-Ray Diffraction / Q000295:instrumentation* / Q000379:methods
chemical_list: D012996:Solutions; D009113:Muramidase; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase
keywords: MacCHESS; SAXS; high throughput