Taxonomic distribution of proteins containing PWI domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing PWI domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Structure and function of the PWI motif: a novel nucleic acid-binding domain that facilitates pre-mRNA processing.

Szymczyna BR, Bowman J, McCracken S, Pineda-Lucena A, Lu Y, Cox B, Lambermon M, Graveley BR, Arrowsmith CH, Blencowe BJ
Genes Dev. 2003; 17: 461-75

The PWI motif is a highly conserved domain of unknown function in the SRm160 splicing and 3'-end cleavage-stimulatory factor, as well as in several other known or putative pre-mRNA processing components. We show here that the PWI motif is a new type of RNA/DNA-binding domain that has an equal preference for single- and double-stranded nucleic acids. Deletion of the motif prevents SRm160 from binding RNA and stimulating 3'-end cleavage, and its substitution with a heterologous RNA-binding domain restores these functions. The NMR solution structure of the SRm160-PWI motif reveals a novel, four-helix bundle and represents the first example of an alpha-helical fold that can bind single-stranded (ss)RNA. Structure-guided mutagenesis indicates that the same surface is involved in RNA and DNA binding and requires the cooperative action of a highly conserved, adjacent basic region. Thus, the PWI motif is a novel type of nucleic acid-binding domain that likely has multiple important functions in pre-mRNA processing, including SRm160-dependent stimulation of 3'-end formation.