Hmm - MET often has two (or more) conformations.. I would check the anom maps to see where the S atoms are - maybe the CYS S also is partially occupied? Eleanor
On Wed, 17 Jul 2019 at 15:03, Stephen Graham <sc...@cam.ac.uk> wrote: > 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 > ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
