Difficult datasets: Difference between revisions
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Small-molecule and low resolution protein datasets have few reflections per frame. Therefore, the multitude of parameters describing the diffraction experiment probably needs to be reduced. This means that e.g. the following parameters may need adjustment (typical values are given): | Small-molecule and low resolution protein datasets have few reflections per frame. Therefore, the multitude of parameters describing the diffraction experiment probably needs to be reduced. This means that e.g. the following parameters may need adjustment (typical values are given): most importantly | ||
* DELPHI=45 ! to base reflection profiles and refinements on more reflections - try this first if yo get error messages in the INTEGRATE step | |||
and you may also try | |||
* NBATCH=4 ! to reduce the number of scale factors | |||
* REFINE(INTEGRATE)= ! do not refine anything in INTEGRATE; be sure to recycle GXPARM.XDS to XPARM.XDS | |||
* CORRECTIONS= ABSORB ! don't try to correct for MODULATION and DECAY in scaling | |||
Furthermore, you may try to recycle GXPARM.XDS to XPARM.XDS, and to grab the lines e.g. | Furthermore, you may try to recycle GXPARM.XDS to XPARM.XDS, and to grab the lines e.g. | ||
BEAM_DIVERGENCE= 2.067 BEAM_DIVERGENCE_E.S.D.= 0.207 | BEAM_DIVERGENCE= 2.067 BEAM_DIVERGENCE_E.S.D.= 0.207 | ||
REFLECTING_RANGE= 2.303 REFLECTING_RANGE_E.S.D.= 0.329 | REFLECTING_RANGE= 2.303 REFLECTING_RANGE_E.S.D.= 0.329 | ||
from | from INTEGRATE.LP and to insert them into XDS.INP . | ||
Revision as of 20:48, 23 December 2009
Small-molecule and low resolution protein datasets have few reflections per frame. Therefore, the multitude of parameters describing the diffraction experiment probably needs to be reduced. This means that e.g. the following parameters may need adjustment (typical values are given): most importantly
- DELPHI=45 ! to base reflection profiles and refinements on more reflections - try this first if yo get error messages in the INTEGRATE step
and you may also try
- NBATCH=4 ! to reduce the number of scale factors
- REFINE(INTEGRATE)= ! do not refine anything in INTEGRATE; be sure to recycle GXPARM.XDS to XPARM.XDS
- CORRECTIONS= ABSORB ! don't try to correct for MODULATION and DECAY in scaling
Furthermore, you may try to recycle GXPARM.XDS to XPARM.XDS, and to grab the lines e.g.
BEAM_DIVERGENCE= 2.067 BEAM_DIVERGENCE_E.S.D.= 0.207 REFLECTING_RANGE= 2.303 REFLECTING_RANGE_E.S.D.= 0.329
from INTEGRATE.LP and to insert them into XDS.INP .