Some notes on crystallizing fibrinogen and fibrin fragments.

We have recently determined the structure of a native fibrinogen at 2.7-A resolution. Not the least of the hurdles during the many years of this project was growing X-ray-grade crystals from suitably purified proteins. Small, synthetic peptides based on the parts of fibrinogen exposed by the action of thrombin contributed greatly to these experiments. In addition, trimethylamine oxide (TMAO) was found to improve the diffraction of fibrinogen crystals. The history of my interest in fibrinogen and its crystallization can be traced back in part to some early interactions with John Edsall.