Sorry Dale. I left that out. I thought that it was almost parallel or very
close. I guess that is not enough. This is after all an exact science. My
fault.


On Thu, May 8, 2014 at 10:54 AM, Dale Tronrud <[email protected]> wrote:

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>   By the way...  I did not say what you claim I said.  I said there
> is always translational ncs in P21 when there is a ncs 2-fold PARALLEL
> to the crystallographic screw.  Your 2-fold appears to be off-set
> from the screw axis enough that Phaser is not detecting tNCS, which
> means it is not strong enough for it to be a problem for Phaser.
> Whatever your problem is, it is not translational NCS.
>
>    Is there anyone in your area that could help you?  In situations
> like this you need to go back to square one and reevaluate every
> decision you made starting from the images.  This is nearly impossible
> to do remotely.  We do not know your protein.  We do not know how
> your crystal relates to the crystal which you are using as your MR
> probe.  All of the thousand things that can go wrong are unknown to
> us.  Unless you are willing to dump your entire project onto the
> BB there is little we can do for you.
>
> Dale
>
> On 05/08/2014 10:11 AM, Yarrow Madrona wrote:
> > Hello CCP4 community,
> >
> > I am stumped and would love some help. I have a molecular
> > replacement solution that has Rfree stuck around 40% while Rwork is
> > aorund 30%. The model is actually the same enzyme with a similar
> > inhibitor bound. Relevant information is below.
> >
> > -Yarrow
> >
> > I have solved a structure in a P21 spacegroup:
> >
> > 51.53 88.91 89.65, beta = 97.1.
> >
> > Processing stats (XDS) are very good with low Rmerge (~5% overall)
> > and good completeness.
> >
> > I don't think twinning is an option with these unit cell
> > dimensions. My data was highly aniosotropic. I ran the data through
> > the UCLA anisotropic server to scale in the B- direction
> > (http://services.mbi.ucla.edu/anisoscale/)
> >
> > I get a small (a little over 5) patterson peak suggesting there is
> > not much t-NCS to worry about. However, the output structure does
> > have 2 fold symmetry (see below) and as Dale Tronrud pointed out,
> > there is always tNCS in a P21 space group with two monomers related
> > by a 2-fold axis. I calculated the translation to be unit cell
> > fractions of 0.36 0.35, 0.32.
> >
> > rota_matrix   -0.9860   -0.1636   -0.0309 rota_matrix   -0.1659
> > 0.9511    0.2605 rota_matrix   -0.0132    0.2620   -0.9650
> > tran_orth      34.3310  -24.0033  107.0457
> >
> > center_orth   15.7607    7.2426   77.7512 * * *Phaser stats:*
> >
> > *  SOLU SET  RFZ=20.3 TFZ=19.5 PAK=0 LLG=1314 RF++ TFZ=63.8 PAK=0
> > LLG=4745 LLG=4947*
> >
> >
> > *  *
> >
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