ArgoN is the N-terminal domain of argonaute proteins in eukaryotes. ArgoN is composed of an antiparallel four-stranded beta sheet core that has two alpha helices positioned along one face of the sheet and an extended beta strand towards its N-terminus. The core fold of the N domain most closely resembles the catalytic domain of replication-initiator protein Rep. The N domain is linked to the PAZ domain via linker 1 region, and together these three regions are designated the PAZ-containing lobe of argonaute.

1: Crystal structure of A. aeolicus argonaute, a site-specific DNA-guided endoribonuclease, provides insights into RISC-mediated mRNA cleavage. Yuan YR, Pei Y, Ma JB, Kuryavyi V, Zhadina M, Meister G, Chen HY, Dauter Z, Tuschl T, Patel DJ; Mol Cell. 2005;19:405-419. PMID:16061186