Conformational Changes and Flexibility of DNA Devices Observed by Small-Angle X-ray Scattering

Area of Science:

• Biotechnology
• Nanotechnology
• Structural Biology

Background:

• DNA origami enables precise molecular-scale shape creation.
• Dynamic DNA devices offer novel functionalities for diagnostics, therapeutics, and engineering.
• Characterizing conformational changes in solution is crucial for developing advanced DNA devices.

Purpose of the Study:

• To demonstrate small-angle X-ray scattering (SAXS) for resolving DNA origami conformational changes.
• To refine the 3D structure of DNA origami objects using SAXS data and elastic network modeling.
• To establish SAXS as a powerful tool for analyzing dynamic DNA devices in solution.

Main Methods:

• Utilized small-angle X-ray scattering (SAXS) to monitor a DNA origami two-state switch.
• Varied ionic strength to induce and observe conformational state changes.
• Employed a normal mode approach with an elastic network model to refine 3D structures from SAXS data.

Main Results:

• SAXS quantitatively resolved conformational changes in the DNA origami switch based on ionic strength.
• Refined 3D structures revealed deviations from idealized designs, which are difficult to detect otherwise.
• Established SAXS as a viable method for analyzing solution structures and conformational dynamics of DNA origami.

Conclusions:

• SAXS is a powerful, non-labeling, non-surface-attachment technique for studying DNA origami in solution.
• The methodology allows for precise structural refinement and understanding of dynamic DNA nanodevices.
• This approach is expected to be broadly applicable to increasingly complex DNA and RNA devices.