This is the N domain often found in the N-terminal region of Argonaute (AGO) present in Kluyveromyces polyspora. AGO forms part of the RNA-induced silencing complex that mediates the gene silencing pathway, RNA interference. The N domain blocks the nucleic acid-binding channel and prevents propagation of guide-target pairing beyond position 16 [1].

1: Structure of yeast Argonaute with guide RNA. Nakanishi K, Weinberg DE, Bartel DP, Patel DJ; Nature. 2012;486:368-374. PMID:22722195