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*To*: Qinghua Wang <qhw@mrc-lmb.cam.ac.uk>*Subject*: Re: AMORE*From*: Eleanor Dodson <ccp4@yorvic.york.ac.uk>*Date*: Wed, 17 Feb 1999 11:20:41 GMT*Cc*: ccp4bb@dl.ac.uk*In-Reply-To*: Qinghua Wang <qhw@mrc-lmb.cam.ac.uk> "AMORE" (Feb 16, 3:28pm)*References*: <l03010d14b2ef22180b94@[131.111.184.165]>*Sender*: owner-ccp4bb@dl.ac.uk

*** For details on how to be removed from this list visit the *** *** CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html *** I totally approve of your caution in processing the data i P222; systematic absence analysis can be confusing, and a molecular replacement search is an excellent way of distinguishing which possible symmetry is correct. But you have only tested half the necessary set. As phil Jeffries said; as well as P222 ( 16) P2221 (17) P21212 (18) and P212121 (19) you need to test P2122 P2212 P21221 and P22121. The $CLIBD/symop.lib has been extended to include these options: Here are the stdd ones already there: 16 4 4 P222 PG222 ORTHORHOMBIC 'P 2 2 2' X,Y,Z -X,-Y,Z -X,Y,-Z X,-Y,-Z 17 4 4 P2221 PG222 ORTHORHOMBIC 'P 2 2 21' X,Y,Z -X,-Y,1/2+Z -X,Y,1/2-Z X,-Y,-Z 18 4 4 P21212 PG222 ORTHORHOMBIC 'P 21 21 2' X,Y,Z -X,-Y,Z 1/2-X,1/2+Y,-Z 1/2+X,1/2-Y,-Z 19 4 4 P212121 PG222 ORTHORHOMBIC 'P 21 21 21' X,Y,Z 1/2-X,-Y,1/2+Z -X,1/2+Y,1/2-Z 1/2+X,1/2-Y,-Z And here are the extras: 1017 1 1 P2122 PG222 ORTHORHOMBIC 'P 21 2 2' !(unique axis a) X,Y,Z * -X,Y,-Z * 1/2+X,-Y,-Z * 1/2-X,-Y,Z 2017 1 1 P2212 PG222 ORTHORHOMBIC 'P 2 21 2' !(unique axis b) X,Y,Z * X,1/2-Y,-Z * -X,1/2+Y,-Z * -X,-Y,Z 2018 1 1 P21221 PG222 ORTHORHOMBIC 'P 21 2 21' !(unique axis b) X,Y,Z * -X,Y,-Z * 1/2+X,-Y,1/2-Z * 1/2-X,-Y,1/2+Z 3018 1 1 P22121 PG222 ORTHORHOMBIC 'P 2 21 21' !(unique axis a) X,Y,Z * X,-Y,-Z * -X,1/2+Y,1/2-Z * -X,1/2-Y,1/2+Z Add these to your symop.lib, or make your own copy, then test the other four as well. All spacegroups are correct for reflections with h,k,and l even, so you always get a reasonable TRAFUN correlation, but it should be much better fror the correct spacegroup. Once you have chosen which it should be you probably should reindex the crystal to get a standard setting. ie move hkl to klh or lhk to make sure the 21 axes are in the standard system. OK? Eleanor Dodson -- ------------------------------------------------------------------ Eleanor J.Dodson, Chemistry Department, University of York, U.K. Tel: Home +44 (1904) 42 44 49, work: +44 (1904) 43 25 65 ------------------------------------------------------------------

**References**:**AMORE***From:*Qinghua Wang <qhw@mrc-lmb.cam.ac.uk>