[ccp4bb]: Detwin and Molecular Replacement

[Toshimitsu Tanaka <aa06058@mail.ecc.u-tokyo.ac.jp>]

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Hello,everyone.
I hope somebody advise me.
I have a data set that was processed in R3, a=108A,b=108A,c=155A.
First,I tried molecular replacement by using Molrep.
Input pdb file is the same primary sequence.
I show a part of output.
---------------------------------------
                  RF     RF/Sigma 
 Sol-RF1    0.4123E+05  10.73
       2    0.3381E+05   8.80
       3    0.2729E+05   7.10
       4    0.2712E+05   7.06
                 Dens/sig    R-fac    Corr
 Sol-TF1 1        5.14        0.618   0.058
         2        4.74        0.656   0.057   
         3        4.64        0.654   0.059
 Sol-TF2 1        4.98        0.653   0.067
         2        4.61        0.655   0.066
         3        4.52        0.656   0.056
---------------------------------------------

I could not find the solution.
I think this crystal is twin.
Running my data on the Yeates twin server I get back
twin fraction of 0.465.
So,I try to run Detwin and Molrep again.
Thus the following a part of these output.

--------------------------------------------------------------
 Number of reflections written to output file 34282
 Number of omitted because the twin mate was not observed 1

    Dmin   Number   CC_before    CC_after 
                   detwinning   detwinning 
    6.93      890     0.999         0.829  
    4.91     1730     0.999         0.908  
    4.01     2282     0.999         0.907  
    3.48     2570     0.999         0.867  
    3.11     2600     0.998         0.742  
    2.84     2444     0.996         0.551  
    2.63     2124     0.996         0.484  
    2.46     1894     0.994         0.359  
    2.32     1854     0.994         0.362  
    2.20     1622     0.994         0.358  
---------------------------------------
                  RF     RF/Sigma 
 Sol-RF1    0.4517E+05  11.14
       2    0.3215E+05   7.93
       3    0.2829E+05   6.98
       4    0.2828E+05   6.98
                 Dens/sig    R-fac    Corr
 Sol-TF1 1        5.61        0.641   0.060
         2        4.66        0.642   0.054   
         3        4.39        0.638   0.054
 Sol-TF2 1        5.24        0.641   0.057
         2        4.35        0.645   0.050
         3        4.21        0.645   0.047
---------------------------------------------
It is not successful.
I think Detwin does not succeed.
But I don't understand what is wrong.
Is the twin fraction is wrong or not?
What parameter can I change?
How can I proceed this analysis?
Thanks for the support.

--------------------------------
Toshimitsu Tanaka
tel. +81-3-5841-5544
Food Eng. Lab, Univ. Tokyo