Multi-speed sedimentation velocity implementation in UltraScan-III.

Area of Science:

• Biophysical Chemistry
• Analytical Chemistry
• Biochemistry

Background:

• Analytical ultracentrifugation sedimentation velocity (AUC-SV) is a powerful technique for characterizing macromolecules.
• Traditional AUC-SV analysis often assumes constant rotor speed, limiting its application to complex experimental designs.
• Analyzing multi-speed AUC-SV experiments requires advanced computational methods to account for varying experimental conditions.

Purpose of the Study:

• To develop and present a computational framework for the global analysis of multi-speed AUC-SV experiments.
• To extend existing adaptive space-time finite element fitting methods in UltraScan-III for multi-speed data.
• To enable accurate determination of sedimentation and diffusion coefficients from experiments conducted at multiple rotor speeds within a single run.

Main Methods:

• Implementation of extensions to adaptive space-time finite element fitting methods in UltraScan-III.
• Development of optimized optimization routines for fitting arbitrary multi-speed experimental data.
• Incorporation of factors like speed-dependent rotor stretching and radial shifting of boundary conditions.
• Utilization of high-resolution time-state object data from modern AUC instruments.
• Adaptation of unconstrained models for sedimentation and diffusion coefficient extraction.

Main Results:

• A robust framework for global analysis of multi-speed AUC-SV experiments is established.
• The implemented methods successfully account for speed-dependent physical phenomena and experimental noise.
• Optimized grid-based fitting methods effectively handle changes in information content across different speed steps.
• New graphical simulation tools aid in estimating grid metrics and evaluating experimental information content.

Conclusions:

• The presented framework significantly enhances the capability of analyzing complex multi-speed AUC-SV experiments.
• UltraScan-III's extended capabilities provide reliable extraction of sedimentation and diffusion coefficients without prior assumptions.
• The developed tools facilitate improved experimental design and data interpretation in AUC studies.