Crystal structure made easy

Courtesy of the International Union of Crystallography

Crystallizing proteins is a daunting task. Last year Alexander McPherson of the University of California, Irvine, and colleagues proposed a novel strategy to develop crystals quickly by including high concentrations of small molecules to the so-called mother liquors. They analyzed data on the crystallization of 81 different protein cultured in the presence of small molecules that could serve as ligands and potentially promote lattice formation. Recently they examined nine of those crystal structures and looked for evidence that the small molecules indeed aided crystallization. ¹

Small molecule cocktails helped in many cases. In two particular instances, RNase A and bovine trypsin, researchers saw that the bioactive compounds in the reagent mixtures were nearly wholly responsible for creating the unique crystal forms that had never before been observed.

?This work confirms the validity of a new crystallization strategy.? writes Faculty of 1000 member Fred Dyda of the National Institutes of Health. ?The results indicate that, from the mixture, only one of the compounds is localized in the crystal, forming multiple interactions with several protein molecules, thereby promoting crystal lattice formation. This suggests that the application of new crystallization screens using a number of these ?bioactive? small molecule mixes could be a very effective way to improve on the likelihood of success in protein crystallization experiments.?

These papers were selected from multiple disciplines from the Faculty of 1000, a web-based literature awareness tool (www.f1000biology.com).