El 24/01/12 18:56, Greg Costakes escribió: > Whoops, I misspoke... I meant Rsym and Rmerge increase with higher > redundancies. >
But then suppose that one merges data from a crystal that is degrading while exposed, sp the data gets degraded. This is not at all unusual. In the absence of a deep understanding of refinement, intuition suggests that degraded data should produce degraded models. If Rwork and Rfree are measuring anything useful they should go up redundancy in those not-so-unusual cases. Or intuition is misguiding me again. -- Miguel > ------------------------------------------------------------------------------- > Greg Costakes > PhD Candidate > Department of Structural Biology > Purdue University > Hockmeyer Hall, Room 320 > 240 S. Martin Jischke Drive, West Lafayette, IN 47907 > > -------------------------------------------------------------------------------- > ** Hard work often pays of in time, but Procrastination always pays off > now ** > > ------------------------------------------------------------------------ > *From: *"Dale Tronrud" <det...@uoxray.uoregon.edu> > *To: *"Greg Costakes" <gcost...@purdue.edu> > *Cc: *CCP4BB@JISCMAIL.AC.UK > *Sent: *Tuesday, January 24, 2012 12:43:43 PM > *Subject: *Re: [ccp4bb] Problem with getting Rfree and Rf down > > > Is this observation about redundancies a general rule that I missed? > It seems rather surprising to me. What have results have others seen? > > Dale Tronrud > > On 01/24/12 07:23, Greg Costakes wrote: >> snip... > >> Higher redundancies (>7 or so) do tend to increase overall R/Rfree. > >> snip... >> > ------------------------------------------------------------------------------- >> Greg Costakes >> PhD Candidate >> Department of Structural Biology >> Purdue University >> Hockmeyer Hall, Room 320 >> 240 S. Martin Jischke Drive, West Lafayette, IN 47907 >> >> > -------------------------------------------------------------------------------- >> ** Hard work often pays of in time, but Procrastination always pays off >> now ** >> >> ------------------------------------------------------------------------ >> *From: *"Sam Arnosti" <meisam.nosr...@gmail.com> >> *To: *CCP4BB@JISCMAIL.AC.UK >> *Sent: *Monday, January 23, 2012 4:48:50 PM >> *Subject: *[ccp4bb] Problem with getting Rfree and Rf down >> >> Hi every one >> >> I have some crystals in the space group P3121. I collect 180 frames of > data. >> >> My crystals do not diffract better than at most 2.0 angstrom, but the Rf >> barely goes below 23%, >> >> and Rfree also remains somewhere between 28-33%. I have tried to refine >> my data as much as I can. >> >> I do not know whether the problem is because of the bad diffraction or >> collecting extra frames. >> >> The structure factors are also high but they get better as the crystals >> diffract better. >> >> Thanks >> >> Sam -- Miguel Architecture et Fonction des Macromolécules Biologiques (UMR6098) CNRS, Universités d'Aix-Marseille I & II Case 932, 163 Avenue de Luminy, 13288 Marseille cedex 9, France Tel: +33(0) 491 82 55 93 Fax: +33(0) 491 26 67 20 mailto:miguel.ortiz-lombar...@afmb.univ-mrs.fr http://www.afmb.univ-mrs.fr/Miguel-Ortiz-Lombardia
