Proteins on the edge of stability

Proteins harbor regions with split personalities, as suggested by findings from Ying Zhang, Boguslaw Stec, and Adam Godzik (Burnham Institute, La Jolla, CA). Straddling the edge of order and disorder, these dual personality (DP) fragments might be common regulation sites.

Ordered parts of protein structures can be revealed by crystallography, while disorder is usually hidden. Occasionally, solving a structure under a new condition reveals previously unseen protein parts. Scientists usually consider the exposure an improvement, especially if a new structure is obtained at a better resolution, and might even discard previous “inferior” models.

“I believe that's wrong,” says Godzik. “Different conditions have changed the protein; these are independent experiments.” In the new work, his group compared independently solved—previously thought of...