Hi Robert, Because of its high sigma level, it looks like you have a disulfide bond between your cys and a b-mercaptoethanol molecule, In this case, the ethyl group of b-ME might be disordered because of its apolar property.
Fred F --- En date de : Jeu, 9.7.09, Cheng, Robert <[email protected]> a écrit : De: Cheng, Robert <[email protected]> Objet: [ccp4bb] modified cysteine À: [email protected] Date: jeudi 9 Juillet 2009, 5 h 05 Hi all I am refining this structure and encountered this extra blob of density on a cysteine residue. It looks like the cysteine has been modified in some way. The density seems very strong (remain visible at 5sigma fofc). I wonder if someone could tell me what modification has taken place. The density would fit a MET residue perfectly but DNA sequence confirms it is a cys. The buffer contains b-mercaptoethanol, PEG, MgAcetate, Tris, Hepes, NaCl and glycerol. Many thanks for your help. Robert Evotec (UK) Ltd is a limited company registered in England and Wales. Registration number:2674265. Registered Office: 114 Milton Park, Abingdon, Oxfordshire, OX14 4SA, United Kingdom Offrez un compte Flickr Pro à vos amis et à votre famille. http://www.flickr.com/gift/
