Hi all, We've spotted something very weird in our density that we're struggling to reconcile...we have two sulfur atoms (from Met and Cys residues) that are very close together. The density looks for all the world like the methyl group from the Met should also be bonding to the Cys, although obviously the non-bonded terms are keeping them apart during refinement. The dmin is 1.72 and R/RFree are ~0.18/0.20 so the density should be pretty believable. We've seen the same in two crystals. Interestingly, we don't see much change in density if we process just the first/last quarter of the dataset so it isn't overly sensitive to radiation damage during collection.
I posted a short vid on Twitter to illustrate: https://twitter.com/i/status/1151488524425814016 Has anyone ever seen something like this? Is a (Cys)CA-CB-SG-CE-SD-CG-CB-CA(Met) bond possible? Thanks, Stephen -- Dr Stephen Graham Sir Henry Dale Fellow and University Lecturer Department of Pathology University of Cambridge Tennis Court Road Cambridge CB2 1QP http://www.path.cam.ac.uk/research/investigators/graham/ ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
