This family consists of protein sequences that are similar to the nuclease A inhibitor expressed by bacteria of the genus Anabaena ((NuiA, Swiss:Q44296). This sequence is organised to form an alpha-beta-alpha sandwich fold, which is similar to the PR-1-like fold. NuiA interacts with nuclease A by means of residues located at one end of the molecule, including residues making up the loop between helices III and IV and the loop between strands C and D. The mechanism of inhibition of nuclease A by NuiA is as yet incompletely understood [1].

1: The nuclease A inhibitor represents a new variation of the rare PR-1 fold. Kirby TW, Mueller GA, DeRose EF, Lebetkin MS, Meiss G, Pingoud A, London RE; J Mol Biol 2002;320:771-782. PMID:12095254