Protein argonaute, Pyrococcus furiosus (Ago)

PfAgo protein is a DNA-guided nuclease (771 amino acids) that targets cognate DNA and is most active at a temperature range from 87 to 99.9 °C.11b It utilizes short 5'-phospho-ssDNA sequences as guides (gDNA) to bind complementary target strands, resulting in cleavage of the target DNA (tDNA). It endonucleolytically cleaves DNA in short dsDNA (the gDNA indicates where to cleave on the tDNA). It can efficient guide-dependent target DNA cleavage requires a minimal gDNA length of 15 nucleotides (nt) and works up to at least 31 nt. Overexpression of PfAgo decreases plasmid transformation efficiency.It has no appreciable activity with gRNA or on target RNA. It also has guide-independent activity on plasmid DNA called 'chopping'.