When we were working on PheRS we noticed that our protein preps (and crystals) had shades of color: sometimes they were pinkish and sometimes yellowish, or even blueish (and often colorless)! We solved the structure eventually and found a new metal-binding microdomain previously not found in these transferases. The funky colors were caused by the microdomain binding various metals, depending on how those particular fermentations were done and how many purification steps were taken :) In the deposited structure luck of the draw had Zn in the site. It just goes to show that proteins have plenty of tricks left up their metaphorical sleeves.
Artem On Sat, Nov 5, 2011 at 11:15 PM, Craig A. Bingman <cbing...@biochem.wisc.edu > wrote: > In another thread, you indicated that there were no identifiable cofactor > binding sites in your protein, so we are down to less common situations. > Some proteins are spontaneously decorated with pyridoxal on surface lysine > residues. In some cases, this has absolutely nothing to do with the > enzymatic activity of the protein. > > On Nov 5, 2011, at 5:02 PM, Caitlyn Claire Yeykal wrote: > > > Hi -- has anyone had crystals that are colored in regular (unpolarized) > light? Mine are yellow, and I'm not aware of anything in the buffer > conditions that might cause this. I read online that glutaraldehyde can > turn protein crystals a golden color, but as far as I know there isn't any > of that in the well. Purified in HBS pH 7.2; crystallized in > LiCl/PEG4K/Tris pH 8. Any explanations? > > > > Thanks! > > Caitlyn > > > > ____________________________________ > > Caitlyn C. Yeykal > > Mrksich Group/Adams Group > > Dept. of Biochemistry, University of Chicago > > 929 E. 57th St., Rm 547B > > Chicago, IL 60615 > > cait...@uchicago.edu >
