[ccp4bb]: pseudo-ncs restraints?

[Phoebe Rice <price@midway.uchicago.edu>]

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Is there a way, in either cns or refmac, to apply ncs restraints to the 
backbone atoms of DNA chains with different sequences?  I have a 
homodimeric protein bound to an asymmetric DNA site that is present in the 
crystal in two orientations.  When both orientations are refined at once 
they diverge.  This might reflect two conformations but I think it really 
results from a fairly crude model at "modest" (~2.7-2.8) resolution being 
given more freedom than it deserves.  CNS politely reads restraint 
definitions that specifiy only backbone atoms but then quietly doesn't use 
them when the nt sequence differs.
One could probably just refine a partially-wrong but truly symmetric 
sequence, but I was hoping for something more elegant.
	thanks,
	Phoebe