[RASMB] combining DLS and sedimentation equilibrium to get molecular shape

[David Lee]

Dear colleagues,
I am writing to enquire about the validity and pitfalls of modeling  
hydrodynamic shape by combining sedimentation equilibrium data with  
dynamic light scattering data.  I didn't have enough protein for  
sedimentation velocity experiments so after performing sedimentation  
equilibrium experiments, whcih showed the complex to behave as a  
single ideal species, I measured the hydrodynamic radius by dynamic  
light scattering, then calculated the frictional coefficient f.  I  
combined this number with the molecular weight obtained from the  
equilibrium experiment to  calculate s* which I entered along with  
the other data into SEDNTERP  to model the dimensions of the protein  
as a prolate ellipse.  Is this a valid way of  doing hydrodynamic  
modeling?  I'm worried that I'm overlooking something.  Thanks in  
advance for your input on this matter.

Sincerely,
Dave