Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: XendoU is the first endoribonuclease described in higher eukaryotes as being involved in the endonucleolytic processing of intron-encoded small nucleolar RNAs. It is conserved among eukaryotes and its viral homologue is essential in SARS replication and transcription. The large-scale purification and crystallization of recombinant XendoU are reported. The tendency of the recombinant enzyme to aggregate could be reversed upon the addition of chelating agents (EDTA, imidazole): aggregation is a potential drawback when purifying and crystallizing His-tagged proteins, which are widely used, especially in highthroughput structural studies. Purified monodisperse XendoU crystallized in two different space groups: trigonal P3 1 21, diffracting to low resolution, and monoclinic C2, diffracting to higher resolution.

Structural Biology and Crystallization Communications Large-scale purification and crystallization of the endoribonuclease XendoU: troubleshooting with His-tagged proteins