Macromolecular crystal data phased by negative-stained electron-microscopy reconstructions

The combination of transmission electron microscopy with X-­ray diffraction data is usually limited to relatively large particles. Here, the approach is continued one step further by utilizing negative staining, a technique that is of wider applicability than cryo-electron microscopy, to produce models of medium-size proteins suitable for molecular replacement. The technique was used to solve the crystal structure of the dodecameric type II dehydroquinase enzyme from Candida albicans (∼190 kDa) and that of the orthologous Streptomyces coelicolor protein.