[RASMB] protein polymer analysis

[Tina Daviter]

Dear all,

I'd like some opinions on what to get out of running AUC and SEC-MALS 
from samples that are protein mono/oligo/polymer mixes with different 
distributions (monomer up to about 20mers). The monomer size is 52 kDa, 
and samples can be prepared the polymer ladders of which look different 
on native gel. Also, some species have visible double bands, suggesting 
different shapes. I attach a picture. Polymers are extremely stable and 
don't re-distribute upon dilution, yet, SEC does not result in separated 
peaks I am told.

Questions are, for AUC,
- Can we expect peak separation in AUC?
- Can we get reliable shape information for each peak? Which model to 
use for fitting, straight into c(s,ff0)?
- Would running the monomer alone help for data analysis of the polymer? 
(How?)
- What speed to run at if we want to focus on, say, tetramer to decamer 
size?

Regarding SEC-MALS, it's inviting as it's so much quicker, but not sure 
about information content:
- Would slicing a peak in exactly the same way for different samples 
still give information on the different size distributions, even though 
it's averaged?
- I expect no shape information to be had?

Any input/experiences regarding this would be most welcome.

Thanks a lot in advance!
Best wishes
Tina


-- 
Dr. Tina Daviter
ISMB Biophysics Centre
Birkbeck, Univ. of London
London, UK

T 020 70790749
E t.daviter at mail.cryst.bbk.ac.uk
W http://biophysics.ismb.lon.ac.uk

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