Preliminary diffraction data for crystals of ribonucleases A and B and their complexes with deoxy(pA)4 and deoxy(pA)6.

Crystals suitable for three-dimensional x-ray diffraction analysis have been reproducibly grown of both pancreatic ribonuclease A and B, and also of their complexes with deoxy-(pA)4 and deoxy-(pA)6. The crystals, all of which are grown from polyethylene glycol 4000 at low ionic strength, diffract to high resolution and would seem to provide another opportunity for the direct visualization of a protein-nucleic acid interaction.