Volume 6, Number 2, p.p. 91-102
SEGAL, a semi-automatic program for fitting sedimentation equilibrium patterns from analytical ultracentrifugation
Gia Machaidze and Ariel Lustig
M. E. Mueller Institute of Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
The paper describes a computer program (available for PC and Mac) for the evaluation of molecular weights from sedimentation equilibrium centrifuge runs using the Beckman XL-A/XL-I ultracentrifuge. The program can be used with both absorption and interference optical records, and requires no prior assumptions about the nature of the system under investigation (ideal, non-ideal, monodisperse, polydisperse, self-associating etc.). The user can simply choose and change the range of patterns for fitting to the data and simultaneously see the fitting result until the correlation is optimum. It is possible to produce fits to two parts of the same curve if more than one component is expected. The program can be used for the analysis of ultracentrifugation results for 2 and 6 sector centrifuge cells. The program supports the export of fitted data as text files, and can save the fitted images. The user-friendly interface, easy curve manipulation and simultaneous fitting make the program attractive for a wide range of users.
Keywords:
analytical ultracentrifugation, curve fitting, molecular mass determination, sedimentation equilibrium