What does anomalous difference Fourier look like? -----Original Message----- From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of Annemarie Weber Sent: Monday, February 03, 2014 11:37 AM To: [email protected] Subject: [ccp4bb] unexplained density
Dear all, I am refining a 1.4 A resolution structure and found some well-defined but unfortunately unexplained density. The protein was purified in HEPES buffer with PMSF and protease inhibitor cocktail tablets (Roche) added. It was cocrystallized with AMPPNP in PEG2000MME and Tris. I modelled a molecule into the density, which fits quite well but I do not know what it is and how it got there. Attached are two pictures with the difference density and the molecule I modelled in there. Has anybody seen something like this before? Maybe some degradation product of the buffer/PMSF? Any suggestions will be highly welcome. Thanks a lot Annemarie 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 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.
