BER Structural Biology and Imaging Resources
Synchrotron, Neutron, and Cryo-EM
U.S. Department of Energy | Office of Science | Office of Biological and Environmental Research

Solution X-ray Scattering (SAXS)

Static and dynamic structural information on macromolecules in solution

Left: Solution X-ray scattering (SAXS) enables high-throughput structural characterizations of gene products in solution. The technique can distinguish between aggregated and unfolded proteins, define global structural parameters and oligomeric states for most samples, identify shapes and structures similar to unknown structures, and determine protein envelopes. Right: SAXS reveals how protein-mediated reorganization of microbial DNA adapts E. coli to a changing environment. Experimental SAXS curves (left) indicate that HU, a histone-like nucleoid-associated protein (blue and cyan structures at right), organizes the structure of the nucleoid (yellow) differently at a high salt concentration (300mM) than at lower concentrations (50-150mM). This, in turn, affects global gene regulation in the cell. [Left: From Hura, G. L., et al. 2009. “Robust, High-Throughput Solution Structural Analyses by Small Angle X-ray Scattering (SAXS),” Nature Methods 6, 606–12. DOI: 10.1038/NMETH.1353.] Right: Reprinted under a Creative Commons Attribution 4.0 International (CC BY 4.0) license from Remesh, S. G., et. al. 2020. “Nucleoid remodeling during environmental adaptation is regulated by HU-dependent DNA bundling,” Nature Communications 11, 2905. DOI: 10.1038/s41467-020-16724-5.]

Solution X-ray scattering provides information about macromolecular structure and dynamics from solutions or partially ordered arrays of biomolecules under physiologically relevant conditions. This type of X-ray scattering is frequently referred to as small angle X-ray scattering (SAXS) because structural information is most often detected at small angles relative to the probing X-ray beam. SAXS captures information at a lower resolution than macromolecular crystallography or cryo-electron microscopy, so most investigators use the technique to characterize macromolecular behavior in solution at the nanometer scale.

SAXS is a powerful tool for time-resolved studies investigating large conformational changes during enzyme reactions, protein-protein interactions, and protein folding intermediates. An advantage to performing SAXS at a synchrotron experimental station is that data can be collected during sample elution from attached purification columns. This enables unique access to transient complexes that rapidly assemble and disassemble and observations of the effects of varied solution conditions on stabilizing complexes or processes.

Preparation of samples in solution for SAXS is relatively simple, enabling high-throughput data collection. In an era where mutations are easily introduced or sequence variants are contrasted, high-throughput screening allows hundreds of constructs to be characterized within hours. SAXS is therefore an ideal assessment tool for use in the iterative design cycle of macromolecular engineering. While structurally homogeneous samples enable the extraction of more detailed structural information than heterogeneous samples, scattering from heterogeneous materials can also be used to characterize changes in the degree of ordering used to monitor, for example, the degradation of cellulose.

Key Features of SAXS

  • Rapid processing (ms) of small sample volumes (µL) in solution (almost any condition)
  • Data collection during sample purification can increase homogeneity
  • Capture of nanometer-scale information in solutions
  • High-throughput collection of hundreds of samples in hours
  • Data collection at any step of a microfluidic processing scheme

BER Researchers Use SAXS to Study:

See more examples in Science Highlights

Sample Considerations

  • Microliter volumes of solution at mg/mL concentrations
  • More information with homogenous samples
  • Greater degree of scattering with electron-rich atoms
  • Greater degree of scattering with larger particles
  • Requires comparison between solution with and without macromolecule of interest

SAXS Beamlines at DOE User Facilities

Each beamline has unique characteristics. To determine the user facility and beamline best suited to your science questions, see additional information and beamline contacts at the links below.

Research Highlights

DateTitleTechniqueFacilityScience Topic
02/11/2021A Modular Approach to Designing Protein AssembliesSolution X-ray ScatteringAdvanced Light SourceMolecular Structure
01/19/2021Fusion Enzymes Improve Yield of Functionalized TerpenesSolution X-ray ScatteringAdvanced Light SourceMolecular Structure
01/06/2021Designing a Controllable Self-Assembling BiomaterialSolution X-ray ScatteringAdvanced Light SourceMolecular Structure
02/03/2020Antibodies Elicited by Zika Vaccine CharacterizedX-ray Macromolecular CrystallographyAdvanced Photon Source, National Synchrotron Light Source IIMolecular Structure
09/24/2019Revealing a MERS-CoV VulnerabilityX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
10/27/2020Potent Antibody Against SARS-CoV-2X-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
02/02/2021SARS-CoV-2 Enzyme Structure Reveals Potential InhibitorsX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
05/21/2021Essential Enzyme in Bacterial Protein SynthesisX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
06/02/2021Complexation of Metals with Bacterial MethanobactinsX-ray Absorption and Emission SpectroscopyStanford Synchrotron Radiation LightsourceChemical and Elemental Information
03/24/2021Deciphering the Mechanism of Enzymatic Methane SynthesisX-ray Absorption and Emission Spectroscopy, X-ray Fluorescence ImagingStanford Synchrotron Radiation LightsourceChemical and Elemental Information
10/30/2020Molecular Crystals Hybridized with Hydrogel Polymers Achieve Unprecedented Material Attributes
01/07/2020Multistep Crystallization of Microbial S-Layers
03/23/2020Antibiotics with a Built-in OFF Switch
11/02/2020Mechanistic Insights into Cu(I) Biogenesis of Galactose Oxidase
09/01/2020Tracking Foliar Zinc Absorption in Apple Trees
01/01/2021Soil Amendments and Flooding Cycle Impact Cadmium Bioavailability in Paddy Soil
08/18/2020Visualizing Enzymes in Action
01/22/2020Efficient and Economical Strategy for Functional Metalloprotein Design
03/10/2020Introducing Positive Charges in an Artificial Enzyme Increases CO2 Hydrogenation
12/09/2019Tuning the Catalytic Bias of Hydrogenase Enzymes
03/08/2018Safety Concerns Over Tungsten Accumulation in Bone
07/08/2019Nanoparticle Properties Influence Transport and Distribution in Plants
10/17/20183.7-Billion-Year-Old Rock Structures Formed by Tectonics, Not Life
09/07/2018First X-ray Nanofluorescence Tomography of Single Bacterial Cell
12/10/2018Nanoparticle Surface Chemistry Influences Journey Through Tomato Plant
11/07/2017Characterization of Elusive Yeast Protein Complex Involved in Autophagy
03/24/2020Critical Structural Differences Between Seasonal and Pandemic Influenza
03/24/2020Tunable Molecular Coating Stabilizes "DNA Origami" Structures
05/16/2019Key Drug Target Shown Assembling in Real Time
06/17/2021Surface Features of Prions Reveal Mechanism of Replication
01/10/2018Novel Architecture of a Bacterial Plasma Membrane Transporter
11/16/20173D Protein Structure Aids Search for Vaccine
08/09/2018Activation Mechanism of a Protein Kinase Reveals Role in Cancer Proliferation
10/08/2018Searching for New Ways to Fight Bacterial ResistanceNational Synchrotron Light Source II
06/21/2019Light Teaches Coenzymes New TricksX-ray Macromolecular CrystallographyNational Synchrotron Light Source IIMolecular Structure
05/21/2019Structural Basis of Bacterial Spore GerminationX-ray Macromolecular CrystallographyNational Synchrotron Light Source IIMolecular Structure
05/07/2020Mechanism of Activation of a Plant MetacaspaseX-ray Macromolecular CrystallographyNational Synchrotron Light Source IIMolecular Structure
04/14/2021Molecular Fragment Screening Identifies Potential SARS-CoV-2 InhibitorsX-ray Macromolecular CrystallographyAdvanced Light Source, National Synchrotron Light Source II, Stanford Synchrotron Radiation LightsourceMolecular Structure
06/13/2018Structure of a Nuclear Membrane GatekeeperX-ray Macromolecular CrystallographyNational Synchrotron Light Source IIMolecular Structure
09/23/2019Mechanism of Regulatory Protein's Dual Role as Inhibitor and ActivatorX-ray Macromolecular CrystallographyNational Synchrotron Light Source II, Stanford Synchrotron Radiation LightsourceMolecular Structure
04/02/2013Major Scaffold Component in Nuclear Pore ComplexSolution X-ray ScatteringStanford Synchrotron Radiation LightsourceMolecular Structure
05/24/2012Modulation of Plant Hormones by GH3 ProteinsX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
10/29/2013Common Physical Processes in Different Biomass PretreatmentsSmall-Angle Neutron Scattering, X-ray Macromolecular CrystallographySpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
07/17/2013Lessening X-ray Damage Speeds Protein DiscoveryX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
02/07/2013Lipid Bilayer Composition Regulates Function of Lipid Rafts in Model Cell MembranesSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
12/09/2012Watching the Evolution of a Protein’s FunctionX-ray Absorption and Emission SpectroscopyStanford Synchrotron Radiation LightsourceChemical and Elemental Information
08/15/2013Multifunctionality of an Ebola Virus ProteinX-ray Macromolecular CrystallographyAdvanced Light Source, Advanced Photon Source, Stanford Synchrotron Radiation LightsourceMolecular Structure
09/26/2014Understanding Nitrogen Fixation in BacteriaX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
11/10/2014Self-Assembling Porous Protein Cage Designed for Potential Biotech ApplicationsSolution X-ray Scattering, X-ray Macromolecular CrystallographyAdvanced Light SourceMolecular Structure
08/25/2015Modular Construction on a Biomolecular ScaleX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
06/10/2015Archaeal Enzyme Plays Key Role in Atmospheric Carbon TurnoverX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
09/08/2015Manganese Reduction-Oxidation Drives Plant Debris DecompositionSynchrotron Infrared Hyperspectral Imaging, X-ray Absorption and Emission Spectroscopy, X-ray Fluorescence ImagingAdvanced Light Source, Stanford Synchrotron Radiation LightsourceChemical and Elemental Information
12/07/2016Using Soft X-ray Ptychography to Investigate a Bacterium’s Inner CompassX-ray Absorption and Emission SpectroscopyAdvanced Light SourceChemical and Elemental Information
11/30/2016Crystal Structure of NOV1 Enzyme Reveals Mechanism of ActionX-ray Macromolecular CrystallographyAdvanced Light SourceMolecular Structure
11/15/2016Mapping the Migration of Genetic MaterialSoft X-ray TomographyAdvanced Light SourceCell and Tissue Structure
09/30/2020Understanding an Essential Chaperone ComplexCryo-Electron Microscopy, X-ray Macromolecular CrystallographyAdvanced Photon Source, National Synchrotron Light Source II, Stanford Synchrotron Radiation LightsourceMolecular Structure
07/31/2020Targeting a Critical Molecular Switch in COVID-19Solution X-ray ScatteringNational Synchrotron Light Source IIMolecular Structure
11/30/2020Fine Tuning Drugs to Fight CancerX-ray Macromolecular CrystallographyAdvanced Photon Source, National Synchrotron Light Source IIMolecular Structure
01/12/2016Cellulose Synthesis ComplexSmall-Angle Neutron Scattering, Solution X-ray ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
12/14/2016Hollow Pyramid Unlocks Principles of Protein ArchitectureSolution X-ray ScatteringAdvanced Light SourceMolecular Structure
12/20/2016Detailing the Molecular Roots of Alzheimer’s DiseaseX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
08/15/2016How Your Body Transports Zinc to Protect Your HealthX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
07/20/2017The CRISPR Target-Recognition MechanismX-ray Macromolecular CrystallographyAdvanced Light Source, Stanford Synchrotron Radiation LightsourceMolecular Structure
05/03/2018Dynamic Regulation of Histone Chaperone NucleoplasminSolution X-ray ScatteringStanford Synchrotron Radiation LightsourceMolecular Structure
06/23/2017Revealing How Bacterial Organelles AssembleX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
06/26/2017Molecular Basis of Alternative Tyrosine Biosynthesis in PlantsX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
04/12/2017Green Alga Genome Provides Blueprint to Advance Clean Energy, BioproductsSoft X-ray TomographyAdvanced Light SourceCell and Tissue Structure
10/06/2016Description of Hydration Water in Green Fluorescent Protein SolutionSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
09/29/2017Precise Control of Neutron Contrast in Surfactant Micelles Provides Platform for Membrane Structure StudiesSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
12/22/2016Neutrons Identify Oxygen Activation in LPMO enzymeNeutron Macromolecular Crystallography, X-ray Macromolecular CrystallographyAdvanced Photon Source, Spallation Neutron Source/High Flux Isotope ReactorMolecular Structure
05/23/2017Using Neutrons to Resolve Plasma Membrane Organization in Live BacteriaSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
08/03/2017Chemical Strategy for Conversion of CO2 to BiomassX-ray Macromolecular CrystallographyAdvanced Photon Source, Stanford Synchrotron Radiation LightsourceMolecular Structure
11/19/2020Enhancing Enzyme Catalysis Through Directed EvolutionX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
08/14/2020Phenoxy Radical-Radical Coupling in PlantsX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
06/22/2017Archaeal Abundance on Human Skin Changes with AgeSynchrotron Infrared Hyperspectral ImagingAdvanced Light SourceChemical and Elemental Information
08/11/2017Hacking the Bacterial Social NetworkX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
06/16/2017Engineering Better Plant Cultivars for Iron Uptake by Modifying the Iron Deficiency Response in Arabidopsis thalianaX-ray Fluorescence ImagingAdvanced Photon Source, National Synchrotron Light Source II, Stanford Synchrotron Radiation LightsourceChemical and Elemental Information
05/09/2017Probing S-layer Protein Structural Dynamics with SAXSSolution X-ray ScatteringStanford Synchrotron Radiation LightsourceMolecular Structure
09/08/2017The Origins of Photosynthesis in a Sun-Loving BacteriaX-ray Macromolecular CrystallographyAdvanced Light Source, Advanced Photon SourceMolecular Structure
08/14/2017X-ray Footprinting Solves Mystery of Metal-Breathing ProteinAdvanced Light SourceMolecular Structure
12/05/2016Designing Cyclic Oligomers: Greater than the Sum of Their PartsSolution X-ray Scattering, X-ray Macromolecular CrystallographyAdvanced Light Source, Advanced Photon SourceMolecular Structure
09/09/2017Measuring and Modeling Poplar Root Water Extraction After Drought Using Neutron ImagingNeutron ImagingSpallation Neutron Source/High Flux Isotope ReactorCell and Tissue Structure
06/30/2017Finding New Clues to a Common Respiratory VirusX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
11/02/2017Arsenic Accumulation in Benthic Periphytic BiofilmsX-ray Fluorescence ImagingStanford Synchrotron Radiation LightsourceChemical and Elemental Information
10/01/2016Crystal Clear Imaging Infrared Brings to Light Nanoscale Molecular ArrangementSynchrotron Infrared Hyperspectral ImagingAdvanced Light SourceChemical and Elemental Information
07/10/2017Novel Orange Carotenoid Proteins Shed Light on Evolution of Cyanobacteria PhotoprotectionX-ray Macromolecular CrystallographyAdvanced Light SourceMolecular Structure
01/11/2017Study Pinpoints Most Reactive Areas of Nanoscale ParticlesSynchrotron Infrared Hyperspectral ImagingAdvanced Light SourceChemical and Elemental Information
01/19/2017A Regional Model for Uranium Redox and MobilityX-ray Absorption and Emission SpectroscopyStanford Synchrotron Radiation LightsourceChemical and Elemental Information
04/07/2017Direct Measurement of Protein Dynamics In VivoSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
04/18/2017Could This Enzyme Help Turn Biofuel Waste into Something Useful?X-ray Macromolecular CrystallographyAdvanced Light SourceMolecular Structure
07/11/2017Brown Rot Fungi Reveal a New Approach for Biomass Conversion to Fuels and ChemicalsSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
09/19/2019Dynamics on Cellulose Show Two Important Populations from Neutron Scattering and SimulationsSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
11/15/2017Cyanobacterial Studies Examine Cellular Structure During Nitrogen StarvationSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
12/13/2017Binding of Alternative Substrates to NitrogenaseX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
01/17/2018"Zip Code" Mechanism for Hormone Signaling RevealedX-ray Macromolecular CrystallographyNational Synchrotron Light Source II, Stanford Synchrotron Radiation LightsourceMolecular Structure
01/18/2018Structure of a Flavoenzyme Assembly IntermediateX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
12/14/2017Using Plants to Immobilize and Stabilize Arsenic in the SoilX-ray Absorption and Emission Spectroscopy, X-ray Fluorescence ImagingNational Synchrotron Light Source II, Stanford Synchrotron Radiation LightsourceChemical and Elemental Information
08/30/2018Directed Evolution Mimics Allosteric Activation of EnzymesX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
08/21/2018Potent BacteriaX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
11/15/2018Controlled Self-Assembly of a Designed NucleoproteinSolution X-ray ScatteringStanford Synchrotron Radiation LightsourceMolecular Structure
02/05/2019Peptide Induced Lateral Segregation of Lipids in a BiomembraneSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
02/25/2019Breakthrough Shines Light on Disease-Fighting ProteinCryo-Electron Microscopy, X-ray Macromolecular CrystallographyAdvanced Photon Source, Stanford Synchrotron Radiation LightsourceMolecular Structure
02/18/2019An Efficient and Economical Strategy for the Design of Functional MetalloproteinsX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
02/22/2019DNA Gets a Bigger AlphabetX-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
03/05/2019Understanding Cadmium Distribution in Hyperaccumulating Plants for Efficient PhytoremediationX-ray Fluorescence ImagingStanford Synchrotron Radiation LightsourceChemical and Elemental Information
04/05/2019Influence of Chemically Disrupted Photosynthesis on Cyanobacterial Thylakoid DynamicsSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
04/12/2019What Enables the Fastest Carbon Dioxide Fixation by Reductive Carboxylase?X-ray Macromolecular CrystallographyStanford Synchrotron Radiation LightsourceMolecular Structure
05/03/2019New Approach for Solving Protein Structures from Tiny CrystalsX-ray Macromolecular CrystallographyNational Synchrotron Light Source IIMolecular Structure
07/10/2019Structuring Sweetness: What Makes Stevia 200 Times Sweeter than Sugar?X-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
07/10/2019Structural Characterization of Chitinases from Agave tequilanaSolution X-ray ScatteringStanford Synchrotron Radiation LightsourceMolecular Structure
11/19/2019How Essential Membrane Lipids Interact to Regulate Cellular ProcessesX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
11/29/2019Ammonia-Salt Solvent Promotes Cellulosic Biomass Deconstruction Under Ambient Processing ConditionsSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
12/09/2019Research at the Advanced Photon Source Leads to New Ebola DrugX-ray Macromolecular CrystallographyAdvanced Photon SourceMolecular Structure
08/29/2020How Proteins Remodel DNA in Bacteria Under StressSolution X-ray Scattering, X-ray Macromolecular Crystallography, Soft X-ray TomographyAdvanced Light SourceMolecular Structure, Cell and Tissue Structure
08/13/2020Cell Membrane Proteins Imaged in 3DX-ray Fluorescence ImagingAdvanced Photon Source, National Synchrotron Light Source IIChemical and Elemental Information
07/21/2020Role of Solvents in Efficient Biomass DeconstructionSmall-Angle Neutron ScatteringSpallation Neutron Source/High Flux Isotope ReactorMolecular Structure
02/14/2020How Dinosaur Blood Vessels Preserve Through the AgesSynchrotron Infrared Hyperspectral ImagingAdvanced Light SourceChemical and Elemental Information
06/23/2020Novel Cell Membrane Model Could Be Key to Uncovering New Protein PropertiesCryo-Electron Microscopy, Small-Angle Neutron Scattering, Solution X-ray ScatteringNational Synchrotron Light Source II, Spallation Neutron Source/High Flux Isotope ReactorMolecular Structure, Cell and Tissue Structure
10/07/2020"Missing Link" in Evolutionary History of the Carbon-Fixing Protein RubiscoSolution X-ray ScatteringAdvanced Light SourceMolecular Structure