How to get SAXS beamtime during the APS-U Dark Period

Overview

The BioCAT 18ID beamline will be unavailable from April 17 2023 to late 2024/early 2025 due to the APS-U dark period. During that period, users are encouraged to make SAXS measurements at other bioSAXS beamlines in the US. Information on these beamlines is provided below. We will provide some BioCAT supported time at these facilities, and users can also directly apply for beamtime with these facilities at any time.

BioCAT supported beamtime

BioCAT beamline scientists will work with other facilities to support a limited number of user experiments during the dark period. The goal is to help alleviate burden on facility staff due to a possible increased user demand on other facilities. Every few months BioCAT will work with a different beamline to schedule about a week of time at the beamline. BioCAT will solicit interest from our users, help them plan the experiments, and then the users will apply directly to the facility for beamtime. Assuming enough of BioCAT users get awarded beamtime, the facility will schedule the BioCAT users as a contiguous block of time. A BioCAT scientist will travel to the facility during that block to help support our users’ experiments. We will also assist them after the experiment with data processing/analysis as needed. These BioCAT blocks at a given facility will be announced through our user mailing list.

If you want to know more about this BioCAT supported time at other facilities contact Max Watkins.

Users are also encouraged to directly apply to different SAXS beamlines for time if their experiments can’t be accommodated in our focused slots these other facilities. BioCAT staff are happy to assist with these experiments as we can, such as with experiment planning and data analysis.

General notes

  • Other beamlines and the NIH are interested in tracking where BioCAT users go for beamtime during the APS-U dark period. In order to facilitate this, if you are a BioCAT user who is submitting a proposal at a beamline you haven’t used before we ask that you put “BioCAT” in the proposal title when submitting proposals to another facility (e.g. “SAXS to study protein ABC – BioCAT”). This will also help us provide more support for these experiments at these other facilities.
  • We recommend adding a radical scavenger to your buffer for experiments at other facilities (unlike at BioCAT). So you should consider a reductant or 1-2% glycerol to protect against radiation damage.
  • Other beamlines have different q ranges, particularly the minimum q. This minimum q sets the maximum size of a macromolecule that can be measured at the beamline, as Dmax = pi/qmin. Users should be aware that some macromolecules that can be measured at BioCAT (qmin ~0.0027 1/Å, Dmax ~1160 Å) will not be measurable at other beamlines, so check the q ranges for each beamline if you have large objects
  • BioCAT currently does not plan to do time resolved experiments using our setup at any other beamline during the dark period, due to limitations of experimental capabilities at other beamlines and/or available beamtime.

Other beamlines

BL4-2, Stanford Synchrotron Radiation Light Source (SSRL), SLAC National Accelerator Lab (Menlo Park, CA)

Webpage: https://www-ssrl.slac.stanford.edu/smb-saxs/content/bl4-2

Contacts:

Available modes:

  • Batch SAXS
    • High-throughput with 96-well plate and autosampler
    • Sample volume: 30 uL volume
  • SEC-SAXS and SEC-MALS-SAXS
    • Thermo Fischer UltiMate 3000 UHPLC with autosampler
    • Columns: Superdex 75 Increase, Superdex 200 Increase and Superose 6 Increase PC 3.2/200 columns (3.2 mL)
    • Temperature control available

Specialized capabilities:

  • Time-resolved SAXS using a stopped-flow mixer, deadtime ~1 ms

Additional notes for users:

ID7A, Cornell High Energy Synchrotron Source (CHESS), Cornell University (Ithaca, NY)

Website: https://www.chess.cornell.edu/index.php/macchess/biosaxs

Contacts:

Available modes:

  • Batch SAXS
    • High-throughput with 96-well plate and autosampler
    • Sample volume: 30 uL.
    • Temperature: 4-80 C
  • SEC-SAXS and SEC-MALS-SAXS
    • ATKA pure FPLC
    • Columns: Superdex 200 Increase 10/300 GL and 5/150, Superdex 75 Increase 10/300, Superose 6 Increase 5/150
    • Temperature: 4 C standard, RT possible upon request

Specialized capabilities:

  • High-pressure SAXS, both batch and SEC-SAXS
  • Anaerobic SAXS, both batch and SEC-SAXS (O2 < 30 ppm)

Additional notes for users:

  • Preference is given to in-person beamtime requests, but mail-ins can be accommodated based on staff availability
  • q-range: ~0.006 – 0.7 1/Å (can be varied)

LiX (16ID), National Synchrotron Light Source II (NSLS-II), Brookhaven National Lab (Brookhaven, NY)

Website: https://sites.google.com/view/lixbeamline/

Contacts:

Available modes:

  • Batch SAXS
    • High-throughput with autosampler, either in LiX specific holder or 96 well plates.
    • Sample volume: 60 uL.
  • SEC-SAXS

Additional notes for users:

SIBYLS (12.3.1), Advanced Light Source (ALS), Lawrence Berkeley National Lab (Berkeley, CA)

Website: https://bl1231.als.lbl.gov/

Contacts:

Available modes:

  • Batch SAXS
    • High-throughput with 96-well plate and autosampler
    • Sample volume: 30 uL
  • SEC-SAXS and SEC-MALS-SAXS
    • Agilent 1260 series HPLC
    • Columns: Shodex KW-802.5, 803 and 804, with 150, 700 and 1000 kDa exclusion limits, respectively

Additional notes for users:

  • Available SEC-SAXS columns are silica columns and have a pH range of 3-7.5 and a maximum salt concentration of 500 mM
  • Only mail-in experiments, no on-site experiments
  • q-range: ~0.013 - 0.5 1/Å