Seema,
The problem actually originates from the scaling of the data that
assumes a monomodal distritbution of the intensities. This is not the
case with pseudotranslation and there are two sets of reflections: the
weak, pseudo-absent reflections and the strong reflections. The
scaling that assumes errors to be proportional to the intensity
therefore underestimates the error of the strong reflections and
overestimates the error of the weak ones. What I did was to write a
script that selected the weak and the strong reflections from the
output of XDS and rescale each set. I would then just run Refmac using
each set in turn; the weak ones for rigid body and the strong ones for
restrained refinement. The procedure is described in Oksanen et. al
(2006) Acta Cryst. D62, 1369-1374.
HTH,
Esko
On 17.10.2010, at 19.23, Seema Nath wrote:
Would you please explain how to proceed for "rigid body refinement
against weak reflection" & "normal restrained refinement against
strong reflection".
