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Re: [ccp4bb] Refmac 5.4.0066 versus Refmac 5.4.0034 |
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CCP4bb navigationCCP4bb <-- 2008 <-- January 2008 <-- 02 January 2008Subject: Re: Refmac 5.4.0066 versus Refmac 5.4.0034 From: Garib Murshudov garib {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK Date: 2008-01-02 > On Tuesday 01 January 2008 06:40, Mark A Saper wrote: >> >> Well, I guess one shouldn't change versions of refmac in the middle >> of a structure refinement. What are the major differences between . >> 0034 and .0066 ? I noted that form factors for the Se atom have >> changed dramatically even though I'm using the same " anom formfactor >> SE -8.13 5.05 " command. Is this because the program is now using >> the wavelength on the .MTZ file ? >> >> with .0034: >> >> SE 8.8706 2.4098 5.8196 0.2726 3.9731 15.2372 >> 4.3543 43.8163 2.8409 > > The first coefficient here is wrong. > >> with .0066: >> >> SE 17.0006 2.4098 5.8196 0.2726 3.9731 15.2372 >> 4.3543 43.8163 -11.7969 > > These are the values given for a1, b1, ... a4, b4 in Table 6.1.1.4 > of International Tables for Crystallography Volume C (1995). > > The value of c (-11.7969) corresponds to an f' value of > -14.6378 (= -11.7969 - 2.8409) > > This could only be possible at the inflection point of the Se > anomalous scattering curve, and only for a beam with a very narrow > bandwidth. Current generation beamlines more typically yield an > effective f' of -5e to -10e in practice. We have corrected it. It was due to double addition of f' (one from anom formfactor and one from a la crossec calculation). Now it should not happen Garib > > -- > Ethan A Merritt Courier Deliveries: 1959 NE Pacific > Dept of Biochemistry > Health Sciences Building > University of Washington - Seattle WA 98195-7742 > CCP4bb navigationCCP4bb <-- 2008 <-- January 2008 <-- 02 January 2008 |
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