molecular replacement question

[Y. W. Chen]

Hi,

I have a structure which has one molecule in the asymmetric unit of P6222.  From homologous structures, I believe this monomer forms dimer related by a crystallographic 2-fold.

Having got no obvious solution for cross-rotation function using the monomer as a search model, in space group P6222, I would like to try using the dimer to search in P62.  Since the rotation axis is fixed, I wonder if there is a way to restrict the cross-rotation search to be along a known axis.  I use the CCP4 suite so I would appreciate your advises in response to using CCP4 programs, ie AMORE, ALMN, POLARRFN, and X-PLOR as well.   I suspect I can use POLARRFN and search in the third polar angle (rotation along the axis).  Please advise if there are other methods in doing this.  Thanks in advance.

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Yu Wai CHEN                          Department of Biochemistry
.................................             & Molecular Biology
                                     Faculty of Medicine
  tel: (604)-822 5007                2146 Health Sciences Mall
  fax: (604)-822 5227                University of British Columbia
email: ywchen at laue.biochem.ubc.ca    Vancouver BC  V6T 1Z3   CANADA
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