InterPro domain: IPR016071

Staphylococcus aureus nuclease (SNase) homologues, previously thought to be restricted to bacteria and archaea, are also in eukaryotes. Staphylococcal nuclease has a multi-domain organisation [ 1 ]. The human cellular coactivator p100 contains four repeats, each of which is a SNase homologue. These repeats are unlikely to possess SNase-like activities as each lacks equivalent SNase catalytic residues, yet they may mediate p100's single-stranded DNA-binding function [ 2 ]. A variety of proteins including many that are still uncharacterised belong to this group.

SNase domains have an OB-fold consisting of a closed or partly open beta-barrel with Greek key topology [ 3 ].

1. The human EBNA-2 coactivator p100: multidomain organization and relationship to the staphylococcal nuclease fold and to the tudor protein involved in Drosophila melanogaster development. Biochem. J. 321 ( Pt 1), 125-32
2. P100, a transcriptional coactivator, is a human homologue of staphylococcal nuclease. Protein Sci. 6, 459-63
3. The alpha aneurism: a structural motif revealed in an insertion mutant of staphylococcal nuclease. Proc. Natl. Acad. Sci. U.S.A. 90, 3275-9