I have a question related to protein structure, but not crystallography per se. Has anyone see a disulfide forming between the two cys of "CXC" in the middle of a loop, and create a sharp turn, where X is not a proline? I seems to me that geometrically this would be possible but I am not sure how stable it is, or how energetically unfavorable it might be.
thanks so much for your input! Ronnie
