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Hi James, I usually use DM in teh CCP4 suite to do DM. It gives you options to do solvent flattening, Histogram matching and NCS averaging. If you compare the FOM to the DMFOM in the mtz files, you can usually see and improvement in the score. That is usually all I bother my arse to look at. Any comments as to what else I should be looking at generally, would be welcomed. I am currently working on a difficult structure at 2.9 Angstrom that I cant get to lower the RFree any more and am stuck at 32% with a R fact of about 21%. I went back and performed density modification right at the start, then performed MR and the same refinement as before and saw absolutely no improvement in refinement statistics at all. They were identical using the non-DM modified mtz file. I was surprised, but this may be due more to the fact that I don't fully appreciate what is going on here. For the record I performed flattening and matching and tried this and then both plus NCS (there is NCS in my model) averaging and still absolutely identical refinement statistics. This is using refmac by the way TLS + restrained refinement. Sorry for the thread hijack James, but at least it is related! ;) cheers andy 2009/4/15 James Stroud <[log in to unmask]>: > Hello All, > > What is the current state of the art with respect to density modification > after molecular replacement? In other words, what programs are people having > the best luck with these days? > > Thanks in advance for any hints. > > James >