Crystallographic study of the anti-tumor protein ricin

The anti-tumor protein ricin (also called RCA_II) has been crystallized in a form suitable for X-ray diffraction analysis. The crystal symmetry is orthorhombic spacegroup P2₁2₁2₁ with $\text{a = 72.9, b = 79.1, c = 114.7}\text{A}\text{?}$ and a single ricin molecule of molecular weight 65,000 per asymmetric unit. The crystals diffract well and are stable in the X-ray beam. At least one useful heavymetal derivative has been found as part of a high-resolution study.