2cystein.jpeg looks just like oxidation of cysteine to S-hydroxy-cysteine (a.k.a. cysteine sulfenic acid). I have seen this repeatedly in one of my structures (E. coli aminopeptidase P, see 1WL9 for an example). We discuss this a bit in Graham et al (2005) Biochemistry 44: 13820-36 - see Figure 2 and surrounding text.
Cheers, Stephen On 8/14/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > Dear all, > > I am refining a 2.0A structure. I found that there were some extra density > on two cysteines, even though I have added 5mM BME in the protein buffer. > > I am wondering whether the first one (Cys292) is a bme and the second one is > an oxidized cysteine. Any suggestion? > > I attached the images for your reference. thanks > > Regards > _________________________________________ > Xu Ting ,Ph.D > 10 Biopolis Road > Singapore 138670 > Fax: +65 6722 2916 > Phone: +65 6722 2980 > -- Dr Stephen Graham Nuffield Medical Fellow Division of Structural Biology Wellcome Trust Centre for Human Genetics Roosevelt Drive Oxford OX3 7BN United Kingdom Phone: +44 1865 287 549
