Characterization of reversible associations by sedimentation velocity with UltraScan

Macromol Biosci. 2010 Jul 7;10(7):775-82. doi: 10.1002/mabi.200900481.


We compare here the utility of sedimentation velocity (SV) to sedimentation equilibrium (SE) analysis for the characterization of reversible systems. Genetic algorithm optimization in UltraScan is used to optimize the model and to obtain solution properties of all components present in the system. We apply our method to synthetic and experimental data, and suggest limits for the accessible kinetic range. We conclude that equilibrium constants obtained from SV and SE analysis are equivalent, but that SV experiments provide better confidence for the K(d), can better account for the presence of contaminants and provide additional information including rate constants and shape parameters.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Algorithms*
  • Chemical Fractionation
  • Computer Simulation
  • DNA-Binding Proteins / metabolism
  • Humans
  • Kinetics
  • Molecular Weight
  • Polycomb Repressive Complex 1
  • Protein Multimerization
  • Ubiquitin-Protein Ligases / metabolism
  • Ultracentrifugation / methods*


  • DNA-Binding Proteins
  • Polycomb Repressive Complex 1
  • RNF2 protein, human
  • Ubiquitin-Protein Ligases