All - I am trying to intuitively understand the concept of the DEN (deformable elastic network) function for low resolution X-ray crystallography in Schroder et al. (Levitt &amp; Brunger) recent Letter to Nature (Vol 464, 22 April 2010).  Is this (conceptually anyway) analogous to an experimentally determined NOE distance restraint between some parts of a structure in an NMR refinement, except here using distance restraints from homologous structures determined at &quot;high&quot; resolution?  I am trying to think of a way to describe it to students without the math.  That may be impossible but I&#39;d like to try!  I should probably have posted this to CNSbb but I don&#39;t currently belong- sorry.<br>
<br>Thanks<br><br>Laurie Betts<br>UNC<br>