Dear Joe, Reflections that correspond to the reflection conditions of your space group symmetry (e.g. h=2n, h+k=2n, l=2n for C4) and are the reciprocal space equivalent of the ligand binding pocket in real space should be considered for comparison. But make sure you collect corresponding reflections also in lower resolution shells (ones that might fall behind the beamstop) as these will have a strong effect on results (Fourier ripples).
or it might be more straight forward to solve the ligand-bound structure ;-) best regards Stefan -----Original Message----- From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] Behalf Of Joe Chen Sent: 28 May 2007 21:35 To: [email protected] Subject: [ccp4bb] How to determine ligand binding from diffraction pattern? Dear all, Is there a simple way to determine whether ligand is bound or not by comparing the diffraction patterns between ligand-free (structure known) and ligand-soaked protein crystals? I would like to solve the ligand bound protein structure, but before I do so, I have to find out if the ligand is actually bound. Thank you very much! Best, Joe
