Having done this a few hundred times, I would strongly suggest that you just collect the data and solve the structure. Since you already have the apo structure solved, then it really isn't that much work to do an MR solution on the complex. Be aware that quite frequently there is enough non-isomorphism to necessitate partial refinement of the "complex" structure before recognizable density will appear for the ligand. The definitive answer can only be obtained with a full data set, so go for it. Good luck- Steve
________________________________ From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Joe Chen Sent: Monday, May 28, 2007 4:35 PM 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 ------------------------------------------------------------------------------ Notice: This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, New Jersey, USA 08889), and/or its affiliates (which may be known outside the United States as Merck Frosst, Merck Sharp & Dohme or MSD and in Japan, as Banyu - direct contact information for affiliates is available at http://www.merck.com/contact/contacts.html) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system. ------------------------------------------------------------------------------
