<p> The PUA (PseudoUridine synthase and Archaeosine transglycosylase) domain was named after the proteins in which it was first found [<cite idref="PUB00003444"/>]. PUA is a highly conserved RNA-binding motif found in a wide range of archaeal, bacterial and eukaryotic proteins, including enzymes that catalyse tRNA and rRNA post-transcriptional modifications, proteins involved in ribosome biogenesis and translation, as well as in enzymes involved in proline biosynthesis [<cite idref="PUB00036064"/>, <cite idref="PUB00036065"/>]. The structures of several PUA-RNA complexes reveal a common RNA recognition surface, but also some versatility in the way in which the motif binds to RNA [<cite idref="PUB00036063"/>]. PUA motifs are involved in dyskeratosis congenita and cancer, pointing to links between RNA metabolism and human diseases [<cite idref="PUB00036066"/>].</p>