Multi‑speed sedimentation velocity implementation in UltraScan‑III
Date
2018
Authors
Gorbet, Gary E.
Mohapatra, Subhashree
Demeler, Borries
Journal Title
Journal ISSN
Volume Title
Publisher
Springer
Abstract
A framework for the global analysis of multi-speed analytical ultracentrifugation sedimentation velocity experiments is
presented. We discuss extensions to the adaptive space–time finite element fitting methods implemented in UltraScan-III to
model sedimentation velocity experiments where a single run is performed at multiple rotor speeds, and describe extensions
in the optimization routines used for fitting experimental data collected at arbitrary multi-speed profiles. Our implementa-
tion considers factors such as speed dependent rotor stretching, the resulting radial shifting of the finite element solution’s
boundary conditions, and changes in the associated time-invariant noise. We also address the calculation of acceleration
rates and acceleration zones from existing radial acceleration and time records, as well as utilization of the time state object
available at high temporal resolution from the new Beckman Optima AUC instrument. Analysis methods in UltraScan-III
support unconstrained models that extract reliable information for both the sedimentation and the diffusion coefficients. These
methods do not rely on any assumptions and allow for arbitrary variations in both sedimentation and diffusion transport.
We have adapted these routines for the multi-speed case, and developed optimized and general grid based fitting methods
to handle changes in the information content of the simulation matrix for different speed steps. New graphical simulation
tools are presented that assist the investigator to estimate suitable grid metrics and evaluate information content based on
edit profiles for individual experiments.
Description
Accepted author manuscript
Keywords
Analytical ultracentrifugation , Finite element modelling , Multi-speed analysis , UltraScan , Sedimentation
Citation
Gorbet, G. E., Mohapatra, S., & Demeler, B. (2018). Multi‑speed sedimentation velocity implementation in UltraScan‑III. European Biophysics Journal, 47(7), 825-835.https://doi.org/10.1007/s00249-018-1297-z