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Dear Ian, Truncating the data to 10A and then filling in the missing hkl values and including them with Fo replaced by e.g. DFc is an established way of improving the maps (at the cost of a little model bias), but the novel twist in your example was the assignment of R-free flags to these missing reflections. Does this also lead to a reduction in the free R?! Best wishes, George On Fri, Oct 28, 2011 at 09:47:26AM +0200, Tim Gruene wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Dear Ian, > > "10.00A" sounds very much like somebody used shelxpro to create an > ins-file from a PDB file and did not correct the SHEL card to include > low resolution data. So the data may well contain data at 84A, but shelx > does not use the data if the SHEL card is left at its default (10 0.1). > > Cheers, > Tim > > P.S.: "obvious" can be just a dangerous word as "trivial"... > > On 10/27/2011 09:31 PM, Ian Tickle wrote: > > Hi, currently Refmac writes the wrong info for the low resolution > > cutoff, for example: > > > > REMARK 3 PROGRAM : REFMAC 5.6.0119 > > REMARK 3 DATA USED IN REFINEMENT. > > REMARK 3 RESOLUTION RANGE HIGH (ANGSTROMS) : 1.00 > > REMARK 3 RESOLUTION RANGE LOW (ANGSTROMS) : 84.35 > > > > In contrast Shel-X puts in: > > > > REMARK 3 RESOLUTION RANGE LOW (ANGSTROMS) : 10.00 > > > > The mtzdump of the MTZ file shows: > > > > 1 NONE -83 0 0 100.00 -27.0 27.0 84.35 1.00 H H > > 2 NONE 0 97 0 100.00 54.9 54.9 84.35 1.00 H K > > 3 ASC 0 83 0 100.00 31.0 31.0 84.35 1.00 H L > > 4 NONE 0.0 1.0 0 100.00 0.95 0.95 84.35 1.00 I FREE > > 5 NONE 0.0 2071.8 435 99.82 125.22 125.22 10.00 1.00 F FP > > 6 NONE 0.9 90.0 435 99.82 2.73 2.73 10.00 1.00 > > Q SIGFP > > > > So obviously what has happened is that the Free R flags have been > > generated to the high resolution cutoff and the low-res reflections, > > i.e. below 10 Ang only have HKL & FREE defined. Somewhere along the > > line (this is data from the PDB) the low-res F's were lost. So IMO > > one cannot claim that these data were "used" in refinement. Getting > > tthe low-res cutoff wrong has a big effect on the electron density > > that one expects for a given resolution range! It seems to me that it > > would be preferable to omit information rather than risk putting in > > the wrong value, at least then one would know to go find the info > > somewhere else. > > > > Cheers > > > > -- Ian > > > > - -- > - -- > Dr Tim Gruene > Institut fuer anorganische Chemie > Tammannstr. 4 > D-37077 Goettingen > > GPG Key ID = A46BEE1A > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.10 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ > > iD8DBQFOql4OUxlJ7aRr7hoRAurhAKCFuKzPjt9uGKlg38/PlIPvEYyK0QCfW3r5 > uOugyeB1TLn8WBjI5cHz66Q= > =72lY > -----END PGP SIGNATURE----- > -- Prof. George M. Sheldrick FRS Dept. Structural Chemistry, University of Goettingen, Tammannstr. 4, D37077 Goettingen, Germany Tel. +49-551-39-3021 or -3068 Fax. +49-551-39-22582