Hello:
I am puzzled (probably shows my lack of understanding) by a REFMAC
output using the TWIN option. My data set is in space group 145 (P32),
with a twinning factor (according to the twining server) of ~ 40% along
a*,b*. In this space group there are three possible twinning operators,
but only this one shows a significant value.
When refining with REFMAC, the program reports 4 twin domains: Here is
the relevant output.
The number of twin domains = 4
Twin domains ((pseudo)merohedral only):
Twin domain 1 with operator: " 1.000H, 1.000K, L" and with
initial fraction = 0.318
Twin domain 2 with operator: "-1.000H, 1.000H+1.000K, -L" and with
initial fraction = 0.227
Twin domain 3 with operator: "-1.000H, -1.000K, L" and with
initial fraction = 0.227
Twin domain 4 with operator: "-1.000H-1.000K, 1.000K, -L" and with
initial fraction = 0.227
---------------------------------------------------------------
So my question: why 4 twin domains? My understanding from the twinning
server is that there are only two twin domains, with a relative
abundance of 40:60.
Thanks.
Arnon
--
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Arnon Lavie, Professor
Dept. of Biochemistry and Molecular Genetics
University of Illinois at Chicago
900 S. Ashland Ave.
Molecular Biology Research Building, Room 1108 (M/C 669)
Chicago, IL 60607
U.S.A.
Tel: (312) 355-5029
Fax: (312) 355-4535
E-mail: [email protected]
http://www.uic.edu/labs/lavie/
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