Re: [ccp4bb]: I222 to P212121

["Gerard \"DVD\" Kleywegt" <gerard@xray.bmc.uu.se>]

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this sounds like the case of cellobiohydrolase I. compare

- 1cel:
CRYST1   84.000   86.200  111.800  90.00  90.00  90.00 P 21 21 2     8

- 3cel:
CRYST1   84.000   84.100  111.500  90.00  90.00  90.00 I 2 2 2       8

1cel has two molecules per asymmetric unit with a translation
of ("almost 1/2",1/2,1/2) in spacegroup P21212 (i.e., 18 not 19 !),
resulting in a "pseudo-I222 packing". in 3cel, the translation
becomes (1/2,1/2,1/2) which "transforms" the spacegroup into I222.

see the paper describing 3cel:
Stahlberg J, Divne C, Koivula A, Piens K, Claeyssens M, Teeri TT,
Jones TA, Activity studies and crystal structures of catalytically
deficient mutants of cellobiohydrolase I from Trichoderma reesei.
J Mol Biol 1996 Nov 29;264(2):337-49. MedLine:
http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?form=6&db=m&Dopt=b&uid=8951380

--gerard

******************************************************************
                        Gerard J.  Kleywegt
Dept. of Cell & Molecular Biology  Bolshevik University of Uppsala
                Biomedical Centre  Box 596
                SE-751 24 Uppsala  SWEDEN

    http://xray.bmc.uu.se/gerard/  mailto:gerard@xray.bmc.uu.se
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