Hi -
ARP/wARP only likes standard space groups, like P21212,
P22121 is not-standard ... oh well ...
(Eleanor is complaining about it for about 13 years ... but never
mind that she is right)
Just re-index your sg to be P21212 (refl. utilities, reindex, in ccp4i).
Choose 'Entering reflection transformation'
P22121 to become P21212 you need
h=l
k=k
l=-h
set SG to p21212
if you are too lazy redo the Molrep or a nice brain teaser is to
apply the correct transformation to your PDB
(PDBSET will do that for you) and you are ready to go with ARP/wARP
A.
PS. depending on cell axes length, and given that convention wants
the smaller 21 axis first,
the formally correct transformation above might be
h=k
k=l
l=h
(in other words if your CURRENT b axis is smaller than your current c
axis its the one above.
if the CURRENT c axis is smaller than b, the use the one on top)
PS2 I think i got the - right, you need to be sure you do not invert
the hand - reindex will complain if I was wrong,
in which case get rid/add a the '-' sign ;-)
On Sep 18, 2007, at 12:28, Florian Schmitzberger wrote:
Dear All,
I am trying to build a molecular replacement model in arp/warp in
space group P22121.
Refmac alone seems to be fine with refining the model in P22121;
but arp/warp fails, as far
as I can see at the first Refmac refinement stage. In the log-file
it says "this space group is
not supported".
I am wondering whether arp/warp needs the Hermann-Mauguin
convention space group
P21212. I suppose I will need to reindex in P21212 in order to use
arp/warp? (the diffraction
data were indexed in XDS, scaled in SCALA, and then run through CAD
to change the space
group from P222 to P22121). I am using arp/warp via the ccp4i
interface.
Also, arp/warp gives the following message when I load the mtz file
"cannot extract
arp/warp asymmetric unit limits, the job will fail if run." (i did
run arp/warp successfully with
other mtz-files).
Thank you in advance for any comments!
Florian
