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Re: AMORE



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On Tue, 16 Feb 1999, Qinghua Wang wrote:

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> 
> Dear all,
> 
>  I am new in crystallography, currently working on solving the structure of
> an important mutant protein, while the xtal structure of the wild type is
> already solved in spacegroup of p212121. In my case, the data were
> processed with MOSFLM in spacegroup of p222. 

Given that this is the case, there are several possible space groups that
could map to your initial P222 assignment:

P222
P222<1>		2<1> parallel to c
P22<1>2		2<1> parallel to b	(permuted non-standard)
P2<1>22		2<1> parallel to a	(permuted non-standard)
P2<1>2<1>2	2 parallel to c
P2<1>22<1>	2 parallel to b		(permuted non-standard)
P22<1>2<1>	2 parallel to c		(permuted non-standard)
P2<1>2<1>2<1>	

and from your AMORE run you've not tested all these possibilties, just
some of them.  Systematic absences might help you pick it out, but that's
not always the case.

Although molecular replacement never ceases to confound any rules I might
suggest, my general experience is that *if* you have a good rotation
function solution (as you appear to) then the mean correlation coefficient
in wrong space groups is often quite high, as you observe.  The
correlation coefficient in the CORRECT space group is even higher, and
quite distinct.  I suspect you've not found the correct space group yet. 
I could be wrong.  In fact, since I'm cc'ing this to CCP4, I'm almost
guaranteed to be wrong (Murphy's/Sod's Law).

Try permuting your axes and run amore again.  (i.e. try hkl permuted to
lhk and klh and rerun AMORE with spacegroups 16,17,18,19 in each case -
remember to reset the unit cell values as you permute).  This is simple to
do in Scalepack, but I don't know about MOSFLM.

Good Luck,
Phil
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| Phil Jeffrey                                  |                             |
| Crystallography Facility Manager              | If you lie to the compiler, |
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