Hello everyone,


I have collected a dataset with a resolution of 1.5 A. The indexing with
denzo went very well with the monoclinic cell (62.3120   84.2860 72.8720
   90.0000  111.9620   90.0000).
After many trials to determine the structure with MR as well as SAD I
thought that my dataset might be twinned. I reindexed the dataset
triclinic and used detwin to analyse it. The found twinning law
corresponds to "-h,-k,l". But nevertheless it was not possible for me to
determine the structure.
I was thinking about a possible twin law in P21 and tried refmac5 with
the keyword "twin" and the monoclinic dataset. Refmac5 found a twinning
law of "-h, -k, l+h" with a twinning fraction of about 20%. Detwin was
not able to deal with these data and gave following error:

*** FATAL ERROR ***
  One of Twin related reflection indices  -15    0   52 exceed maximum
allowed values (   43   59   51)
  Increase PARAMETER MAXIND and recompile.


Is this twinning law correct? For me it looks more like a cell
transformation than a twinnnig law.


Thanks for any help.

Best wishes, Michael


--

     Mag. Michael Karl Uhl
     Research Centre Applied Biocatalyses
     c/o Department of Molecular Biosciences - Structural Biology
         Karl-Franzens-University Graz
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         8010 Graz, Austria

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