An Argonaute from Thermus parvatiensis exhibits endonuclease activity mediated by 5' chemically modified DNA guides.

Prokaryotic Argonaute (pAgo) nucleases with precise DNA cleavage activity show great potential for gene manipulation. Extensive biochemical studies have revealed that recognition of guides with different 5' groups by Ago is important for biocatalysis. Here, we identified an Ago from the thermophilic Thermus parvatiensis ( TpsAgo) and analyzed the regulatory effect of 5'-modified guides on TpsAgo cleavage activity. Recombinant TpsAgo cleaves single-stranded DNA and RNA targets at 65-90°C, which is mediated by a 5' hydroxyl or phosphate DNA guide. Notably, TpsAgo can utilize various 5'-modified DNA guides for catalysis, including 5'-NH 2C 6, 5'-Biotin, 5'-FAM and 5'-SHC 6 guides. Moreover, TpsAgo performs programmable cleavage of double-stranded DNA at temperatures over 80°C and strongly tolerates NaCl concentrations up to 3.2 M. These results provide insight into the catalytic performance of Agos by guide regulation, which may facilitate their biotechnological applications.