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Meng-Chioa Joseph Ho wrote:
Dear All:
I try to do phase extension (from 10 angstrom to 3 angstrom
resolution) by applying two 6-fold NCS averaging in my Asymmetry Unit.
Both NCS operators are parallel to Y-axis of the unit cell.
That seems unlikely, and if it is the case, then averaging is going to
rpesent a number of problems.
In term of set up my NCS operator, how should I do it?
Type rota polar 6 times to define one of my 6 fold NCS operator
ROTA POLAR 0 0 0
ROTA POLAR 90 90 60
>
ROTA POLAR 90 90 120
ROTA POLAR 90 90 180
ROTA POLAR 90 90 240
ROTA POLAR 90 90 300
ROTA POLAR 90 90 360
If it were possible, then you would lose the 360 operator - it is the
same as the first one. Also, the omega and phi angles should be zero.
or I just need to type
ROTA POLAR 0 0 0
ROTA POLAR 90 90 60
This is wrong.
For the TRAN
Should I type fraction or real coordination number for the TRANS?
Orthogonal coordinates. (Coordinates, not coordination number).
And should I do Solvent Flattening and Histogram Mapping too?
Yes, always.
OK, now I've answered your direct questions, I'll tell you what I really
think. If you have a 6-fold exactly parallel to y, then you first need
to check that you've got the spacegroup right.
Next, if you try to derive your operators from scratch, you will get
them wrong unless you are very, very good indeed. I wouldn't try it, and
I wrote the program. If you have heavy atoms, run profess to try and
identify your NCS automatically. If you have a partial model, run lsqkab
or superpose to get the operators automatically.
Other alternatives: Run resolve, or wait a couple of months for the new
version of Pirate.
Kevin
