Protein argonaute

UniProtKB accession:  Q746M7

Grouped By:  Matching UniProtKB accession

UniProtKB description:  A DNA-guided ssDNA endonuclease. Uses short ssDNA sequences as guides (gDNA, also called small interfering DNA, siDNA) to bind complementary DNA target strands, resulting in cleavage of the target DNA (tDNA). The cleavage site is 10 nucleotides (nt) downstream of the target residue base-paired with the 5'-end of the gDNA (PubMed:24531762, PubMed:28911094). Plays a role in completion of DNA replication, participates in decatenating replicated DNA and plasmid. In situ purifies with 5'-phosphorylated long DNA (about 1160 nt, maps to the whole chromosome and plasmid), 25-35 nt RNAs that map to the whole chromosome and 15-18 nt DNA that maps to the replication terminus region (ter) on the chromosome and plasmid. Most short DNA starts with dC (PubMed:32846159). Has been shown to have guide sequence-independent dsDNase activity called 'chopping', which requires unstable DNA (high AT-content, multiple mismatches or low salt conditions), and could be used to generate gDNA. Preferentially binds tDNA with dC at its 3'-terminus (PubMed:28262506). Has also been shown to have no detectable guide sequence-independent dsDNase activity (PubMed:32846159). The latter study proposes TtAgo may acquire gDNA from nicked dsDNA, by binding to 5'-phosphorylated-dC nicks, then cleaving 10 nt away on the opposite strand; subsequently an exonuclease (maybe AddA-AddB helicase/nuclease) trims the ends to generate the gDNA (Probable) (PubMed:32846159).