• 3′-5′ oligoribonucleases;
  • Orn;
  • DEDDh;
  • Xanthomonas campestris.

Oligoribonucleases are essential components of RNA and DNA metabolism and close homologues of genes encoding them are found not only in prokaryotes but also in a wide range of eukaryotes, including yeast and humans. Inactivation of the oligoribonuclease gene (orn) can result in cellular lethality. Despite their important biological function, they have been studied little from a structural point of view. In this report, the cloning, expression, crystallization and preliminary X-ray analysis of XC847, a DEDDh-type 3′-5′ oligoribonuclease from the plant pathogen Xanthomonas campestris pv. campestris, a Gram-negative bacterium causing major worldwide disease of cruciferous crops, is described. The XC847 crystals diffracted to a resolution of at least 2.1 Å. They are tetragonal and belong to space group P43212, with unit-cell parameters a = b = 67.5, c = 89.8 Å. One molecule is present per asymmetric unit.