The Three-Dimensional Structure of Ribonuclease-S

The procedures used in the collection and analysis of x-ray diffraction data from single crystals of ribonuclease-S are described. Both isomorphous and anomalous scattering were measured on heavy atom derivatives prepared with the uranyl cation, the tetracyanoplatinate(II) anion, and dichloroethylenediamine platinum(II). The amplitudes and phases of 6000 reflections were established. An electron density map with an estimated root mean square...