Are fluorescence-detected sedimentation velocity data reliable?

Area of Science:

• Biophysical techniques
• Analytical ultracentrifugation
• Macromolecular analysis

Background:

• Sedimentation velocity analytical ultracentrifugation (SV-AUC) is crucial for studying biological macromolecules.
• Fluorescence detection enhances sensitivity but faces photophysical challenges.
• Standard absorbance and refractrometric detectors have limitations.

Purpose of the Study:

• To detail methods for configuring SV-AUC with fluorescence detection.
• To evaluate the performance and reliability of the fluorescence optical system.
• To compare fluorescence-based SV-AUC results with conventional absorbance measurements.

Main Methods:

• Configured SV-AUC experiments utilizing a fluorescence optical system.
• Assessed detector linearity using fluorescein and Alexa Fluor 488 standards.
• Employed Alexa Fluor 488-labeled duplex DNA as a standard for comparative analysis.
• Validated data acquisition and optical system performance.

Main Results:

• The fluorescence detector demonstrated linear output from 1 to 500nM for tested fluorophores.
• Inner filter effects were identified as a cause for non-linearity at high concentrations.
• Sedimentation coefficients obtained via fluorescence detection closely matched those from absorbance detection.
• No significant differences were observed within error margins.

Conclusions:

• Fluorescence detection is a viable and accurate method for SV-AUC.
• Precise and reliable macromolecular characterization is achievable with proper optical configuration.
• Results are consistent with traditional absorbance-based SV-AUC measurements.