Greetings. I'm wondering if anyone has ever seen something like this. I have a 2.1 A data set (synchrotron data) that is nearing completion. I see density that appears to join a cysteine side chain to a lysine (30 residues away from each other in primary sequence). There is a picture of the density here.
http://labs.hwi.buffalo.edu/gulick/cyslys.html I have modeled this in as a Cysteine sulfenic acid (Side chain is Cb-Sg-OH) and refined. There remains a bit of positive Fo-Fc density above the oxygen and the lysine N and sulfenic acid hydroxyl are 1.8A away. I have some other crazy ideas but haven't been able to find any precedent in the literature. Any thoughts on what this might be or if anyone has seen something similar would be greatly appreciated. Andy -- Andrew M. Gulick, Ph.D. ----------------------------------- (716) 898-8619 Hauptman-Woodward Institute 700 Ellicott St Buffalo, NY 14203 ----------------------------------- Senior Research Scientist Hauptman-Woodward Institute Dept. of Structural Biology, SUNY at Buffalo http://www.hwi.buffalo.edu/Faculty/Gulick/Gulick.html http://labs.hwi.buffalo.edu/gulick