Recent Developments at the Center for Structural Molecular Biology at Oak Ridge National Laboratory
Sai Venkatesh Pingali* (email@example.com), Wellington Leite, Kevin Weiss, Hong- Hai Zhang, Qiu Zhang, Luke Heroux, Volker Urban, and Hugh O’Neill
Oak Ridge National Laboratory (ORNL)
The Center for Structural Molecular Biology (CSMB) at ORNL is a national user facility funded to support and develop the user access and science research program of the Biological Small-Angle Neutron Scattering (Bio-SANS) instrument at the High Flux Isotope Reactor (HFIR). Bio-SANS is dedicated to the analysis of the structure, function and dynamics of complex biological systems. The CSMB also operates a Bios-Deuteration Laboratory for expression and purification of deuterium-labeled biomacromolecules and for synthesis of small molecules and ligands in support of the biology neutron scattering program. This resource complements capabilities at other Department of Energy (DOE) Biological and Environmental Research (BER) program facilities for structural biology. The CSMB supports a vibrant biological research community from academia, industry, and government laboratories.
The Bio-SANS instrument is ideally suited for studies of biomacromolecules including proteins, DNA/RNA, lipid membranes, and other hierarchical complexes. The dual detector system of Bio-SANS allows simultaneous access to a wide spatial range that enables utilization of the full potential of the high neutron flux from the ORNL HFIR cold source. The Bio-SANS detector system is being upgraded to include an additional mid-range detector bank that will greatly benefit time-resolved measurements of a variety of biological systems.
The team has developed a series of new sample environment capabilities that open untapped opportunities for the studies of biological systems using neutrons. A robotic sample changer sample environment has been installed that supports measurement of a range of sample types including solutions, suspensions, powders, and solid materials. It can maintain samples during storage (up to 58) in a desired temperature range between 10 to 70oC. A Peltier heating block at the sample position allows rapid temperature change between 10 to 100oC for in operando measurements. Another example is combined size-exclusion chromatography—SANS for fractionation of biomacromolecules in beam. A novel aspect of this capability is the ability to perform continuous flow measurements as well as fractionation of complex mixtures of biomacromolecules. The flow cell design was improved to ensure reliable and reproducible cell thickness and the flow cell holder has been expanded to accommodate four cells to minimize down time during sequential purifications of multiple proteins. The Bio-SANS data acquisition system and data reduction algorithms have been updated and include the ability to perform wedge- reduction for anisotropic systems such as biomass, and the ability to time-slice data files, which has been invaluable for analysis of time-resolved SANS measurements.
Researchers have expanded the Bio-Deuteration Laboratory to develop small molecule deuteration capabilities. Researchers established the ability to extract and purify deuterated lipid extracts from E. coli and to fractionate the lipid extracts to obtain purified phosphatidylethanolamine and phosphatidylglycerol. Furthermore, the team has produced deuterated phosphatidylcholine from an engineered strain of E. coli. In addition, the team successfully synthesized coniferyl alcohol-d5 as a precursor for deuterated lignin. In the future, this synthetic route will be used to prepare coniferyl alcohol with varying levels of deuterium incorporation and to deuterate other monolignols. Other new laboratory capabilities include preparative high-performance chromatography for separation and purification of different lipids and other small ligands. Analytical ultracentrifugation has recently been acquired and will provide a complementary structural information for biological solution X-ray scattering (SAXS) and SANS studies.
To broaden the impact of the CSMB and catalyze the synergy between BER-funded structural biology resources, the team established collaborative programs with the National Synchrotron Light Source II for joint access to SANS and SAXS and with the BER Facilities Integrating Collaborations for User Science (FICUS) program between the Joint Genome Institute (Lawrence Berkeley National Laboratory) and the Environmental Molecular Sciences Laboratory (Pacific Northwest National Laboratory).
Oak Ridge National Laboratory is managed by UT-Battelle, LLC for the U.S. Department of Energy under contract no. DE-AC05-00OR22725. This program is supported by the U. S. Department of Energy, Office of Science, through the Genomic Science Program, Office of Biological and Environmental Research, under FWP ERKP291.