The AGO (Argonaute) proteins have four domains: an N-terminal domain, the PAZ domain, the MID domain and the PIWI domain. This entry is for the N-terminal domain. The N-terminal domain of AGOs is the most variable domain. Compared with prokaryotic Argonautes, KpAGO (Kluyveromyces polysporus Argonaute) has numerous surface-exposed insertion segments, with a cluster of conserved insertions re-positioning the N domain, contributing to the formation of nucleic-acid-binding channel to enable full propagation of the 3' end of the guide RNA guide-target pairing. The guide strand is used by the RISC complex to specify interactions with target RNAs. If sequence complementarity between guide and target is extensive, AGO catalyses cleavage, resulting in slicing of the target RNA [1].

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