From: Jo Butler <pjgb@mrc-lmb.cam.ac.uk>
  To  : Arturo Morales , rasmb@bbri.org
  Date: Mon, 08 Nov 1999 09:53:49 +0000

Re: Simulating Eq curves

Dear Art,

May one enquire what partial specific volume you are using, to calculate MW
~75Kd?  In the past I have been asked to look at possible protein/RNA
ratios in a complex.  I calculated the v-bar for each possibility and used
this to calculate MW.  In practice it came out that only one ratio gave a
fit of the data to the ratio used to get v-bar.  (Incidentally this
complied with a ratio determined later by other methods.)

Jo

--On Sat, Nov 6, 1999 8:39 pm -0800 Arturo Morales <art@scripps.edu> wrote:

> 
> Hi there,
> 
> We have a RNA:protein system in which we are calculating a MW  ~75Kd.
> This could either represent a 2:1 RNA:protein or a 1:2 complex. (since the
> RNA and the protein monomer are both ~25Kd.  We can make an argument for a
> 1:2 complex since the 260:280 ratio appears to be closer to what we would
> expect in that type of complex (it is not quite 2:1 as we would expect for
> a complex with more RNA than protein.  We would like to model the expected
> eq curves for both possibilites using theoretical data and compare it with
> our actual data.  Altough we have a bunch of different software titles
> that can deal with velocity data, we only have the beckman stuff for
> equilibrium... Any suggestions? :)
> 
> Thanks!
> 
> Art
> 
> ----------------------------------------------------------------------
> Arturo J. Morales    (RPI '94) |  art@scripps.edu
> Department of Biology          | Massachusetts Institute of Technology
>   Skaggs Institute for Chemical Biology - Scripps Research Institute
>                   http://minihelix.mit.edu/art
> 



P.J.G. Butler,
MRC Laboratory of Molecular Biology,
Hills Road,
Cambridge, CB2 2QH,
UK.