I have to use refmac for licencing reasons, sadly, unless someone can recommend an entirely free refinement program to anyone including industry/people in limbo etc.
Actually, I was just thinking. In the new MTZ files (which helpfully I dont have on me) there are new values with 'DM' added to them in the columns e.g. FOMDM instead of DM. If this applied to other labels in the MTZ, would I have to explicitly tell refmac to use them instead of the non-DM label columns? Probably. Blast me leaving the flash drive on my dresser. cheers Andy PS - re:weighting, I have messed about with them quite a bit reducing them to 0.1 seems to get the best results. I struggle onward.....thanks for the replies so far. 2009/4/15 Poul Nissen <p...@mb.au.dk>: > ......and I may add that for DMMULTI two "rather nonisomorphous" data sets > of the same crystal form can work like a dream, in particular at low > resolution where solvent flattening and histogram matching can be tricky, > see for example Morth et al. 2007, Nature 450, 1043 & Pedersen et al. 2007, > Nature 450, 1111 > Poul > On 15/04/2009, at 12.02, Pietro Roversi wrote: > > Dear James and Andy, > my twopenny worth. I am using dm and > dmmulti to solvent > flatten after molecular replacement phases when no shred of experimental > phases is available. If the model is severely incomplete > (say at least 25% missing or more) I use phases from Buster-TNT > refinement with missing atoms modelling switched on (this reduces the model > bias > imp[roves the scaling and helps bringing up weaker features from the > yet unmodelled bits). > > I also blur the phase distribution either by multiplying the FOMs > by a number less than one (say 0.6-0.8) or by doing the same to the > Hendrickson-Lattmann > coefficients (the idea is driectly inspired from this paper: > > Perrakis, A., Harkiolaki, M., Wilson, K. S. & Lamzin, V. S. (2001). > Acta Crystallogr D Biol Crystallogr 57, 1445-1450. > > I tend to try a few values of the multiplicative factor > and choose the one that gives the maps that I like the best. > > Ah: it may be trivial again, but for the project I am working on at the > moment even a 6.7 A dataset > in a different crystal form has made a big difference! the dmmulti fourfold > averaging across > 2 crystal forms being much better than the twofold averaging in dm in the > high-resolution > form. Admittedly this extra crystal form has 90% solvent! So if possible at > all > use dmmulti and multi-crystal averaging. > > I hope this helps! > > Pietro > > -- > Pietro Roversi > EP Abraham Fellow in Biochemistry - Lincoln College - Oxford > Sir William Dunn School of Pathology, Oxford University > South Parks Road, Oxford OX1 3RE, England UK > Tel. 0044-1865-275385 > >
