Re: [ccp4bb]: Indexing problem

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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Konstantinos Beis wrote:
> 
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> 
> Dear All,
> I have collected some data for a new structure and I have problems with my
> indexing. In Mosflm I get the following possible space groups:
> 
> 17  59     cP   137.26   137.69   153.06    90.1  90.1  90.0
> P23,P213,P432,P4232,P4332,P4132
>   16  58     hR   194.36   205.36   247.82    95.2  89.9 118.1   R3,R32
>   15  58     hR   194.36   205.82   247.13    95.1  89.8 118.1   R3,R32
>   14  57     tP   137.69   153.06   137.26    90.1  90.0  90.1
> P4,P41,P42,P43,P422,P4212,P4122,P41212,P4222,P42212 P4322,P43212
>   13  57     oC   205.69   206.06   137.26    90.1  90.1  83.9   C222,C2221
>   12  57     mC   205.69   206.06   137.26    90.1  90.1  83.9   C2
>   11  56     mC   206.06   205.69   137.26    89.9  90.1  96.1   C2
>   10   3     oC   194.47   194.36   153.06    90.0  90.2  89.8   C222,C2221
>    9   3     tP   137.26   137.69   153.06    90.1  90.1  90.0
> P4,P41,P42,P43,P422,P4212,P4122,P41212,P4222,P42212 P4322,P43212
>    8   2     mC   194.47   194.36   153.06    90.0  90.2  90.2   C2
>    7   2     mC   194.47   194.36   153.06    90.0  90.2  89.8   C2
>    6   1     oP   137.26   137.69   153.06    90.1  90.1  90.0
> P222,P2221,P21212,P212121
>    5   1     mP   137.26   137.69   153.06    90.1  90.1  90.0   P2,P21
>    4   1     mP   137.26   153.06   137.69    90.1  90.0  90.1   P2,P21
>    3   1     mP   137.69   137.26   153.06    90.1  90.1  90.0   P2,P21
>    2   0     aP   137.26   137.69   153.06    89.9  89.9  90.0   P1
>    1   0     aP   137.26   137.69   153.06    90.1  90.1  90.0   P1
> 
> So in Mosflm from 10 to 1 I have good fitting.
> 
> When I put those data in SCALA in all the possible groups I get the following:
> 
>                                  I/sigma(overall)
> multiplicity(overall)
> for p1 Rmerge of 5%             5.3                     1.7
> for p21 Rmerge of 11.7%             2.3                  2.2
> for c2 Rmerge of 11.7%  1.6                     2.2
> for p222, p2221......   17%     1.6                     4.2
> for c222, .......      17%              1.6                     4.2
> for p4, ........    36%         0.8                     4.4
> 
> The I/sigma and redundancy  varies according to the space group
> 
> As you can see my a=b, which I think it causes problems with the right
> indexing..
> 


 Why not do a few hklview plots of the P1 data - you should be able to
see likely symmetry. Numbers do not really tell the who;e story - even a
Rmerge of 36% could be due to weak data.
But the eye is very good at seeing how well 2-fold, 4-fold etc symmetry
is obeyed.

 Eleanor






 > In my Scala files it seems that I have p4 pseudosymmetry.
> 
> In the p212121 space group I have good definition for the h.
> 
> Due to that (misindexing) I have problems with my Molecular Replacement.
> 
> Is there something that I might be doing wrong or something that I have not
> noticed? Any help or suggestions are welcomed!
> 
> Kostas
> 
> **********************************************
> Konstantinos Beis
> Centre for Biomolecular Sciences
> University of St Andrews
> North Haugh
> St Andrews
> FIFE KY16 9ST
> 
> tel: +44 1334 427265
> email: kb11@st-andrews.ac.uk
> 
> **********************************************