Mike,
You could try rigid body refinement against the weak reflections to
get the position of the molecules right and then normal restrained
refinement against the strong reflections. I had a case like this some
years ago and that helped...
Esko
On 17.10.2010, at 6.48, Mike John wrote:
Hi all,
The data is 2.2A, p41212, unit cell has c axis twice longer than a
or b. Data processed by HKL2000, the diffraction pattern shows
Strong-weak-weak in C direction, indicating translational pseudo-
symmetry.
Xtriage analysis confirmed the pseudo-symmetry (large Patterson off-
origin peak).
The model is 100% identical searching prob.
Phaser MR solved the structure easily with good Z-score and LLG(3
copies/a.u). The problem comes during the refinement:
The R-free converged around 50% (R-factor 38%) and never go down
even though I tried hard including, twin possibility.
Seeking help to lower the R-free. Thank you very much
Mike
