Zbyszek Otwinowski and Fred Vellieux suggested to run the self-rotation
on Fcalcs. This suggestion "solved" the problem, since there are similar
peaks on the kappa=180° planes as well. However, I wasn't able to get
rid of those peaks by playing around with resolution and integration
radius. I must say that I am surprized, because - as Eleanor pointed out
- I also expected to find peaks on the kappa=180° planes only in case of
P6522 symmetry. Anyway, this experience reminds me to run some simple
tests beforehand.
-Peer
On 29.04.2015 15:31, Eleanor Dodson wrote:
> Well - PG P6/mmm (possible SG P6522) will have peaks at kappa = 180
> omega = 90 phi = 0 30 60 etc..
>
> But if there is only one molecule / asymm unit there cant be an extra
> 2-fold.
>
> How big are the relative domains? Your interesting domain couldnt just
> be cleaved off could it?
> Eleanor
>
>
>
>
>
>
> On 29 April 2015 at 12:59, Peer Mittl <[log in to unmask]
> <mailto:[log in to unmask]>> wrote:
>
> We are working with a multi-domain protein crystallized in SG P6_5
> with one molecule per asymmetric unit. The structure was refined
> at 2.00 A resolution with reasonable R-factors but unfortunately
> the domain we are most interested in seems to be disordered.
> Interestingly, the self-rotation function shows peaks on the
> kappa=180° plane (omega=90°, phi=19° (and every 30°)), with more
> than 50% origin peak height. Therefore, we are wondering if
> perhaps the space group assignment might be sub-optimal. Any
> explanations how these self-rotation peaks could occur and how we
> could extract meaningful information to resolve the disordered
> domain are welcome.
>
> Best regards,
> Peer
>
> P.S. Some additional information: pointless suggests SG P6_5, the
> data doesn't seem to be twinned (L-test), the refined part of the
> structure has no "internal symmetry" and refinement in P1 doesn't
> reveal the "lost" domain.
>
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