From: bgyjpaw@leeds.ac.uk
  To  : rasmb@bbri.org
  Date: Thu, 6 Apr 2000 15:28:55 +0000

RNA vbars

Dear all,

I am currently looking at the self-association of an RNA molecule in 
the presence of Mg2+ through equilibrium sedimentation runs on the
analytical ultracentrifuge.  I am aware that the partial specific volumes 
of nucleic acids can vary with conditions, and was wondering if anyone
had some helpful suggestions about how to approach the problem of
finding a value for vbar.  I have a good molecular weight value for the
RNA monomer from electrospray mass spectrometry, and so at the
moment I hope to find vbar by matching this molecular weight with 
that found on the ultracentrifuge in the absence of Mg2+.   Is this 
an adequate approach, or is there a more direct way of measuring 
vbar?
Hope you can help!

Jonathan Wood  
PhD student 
Astbury Centre for Structural Molecular Biology
University of Leeds
Leeds
UK