Mode of Action of a Nuclease from the Fruit Body of Flammulina velutipes

Abstract

The mode of action of the nuclease from the fruit body of Flammulina velutipes was studied. The nuclease hydrolyzed single-stranded linear polynucleotides exonucleolytically from the 5'-end to produce 5'-mononucleotides. The nuclease also cleaved a single strand of circular DNA endonucleolytically. Single-stranded circular DNA was cleaved by the nuclease to single-stranded linear DNA. The nuclease converted double-stranded circular DNA, which is covalently closed circular DNA, to linear DNA via open circular DNA. Thus the nuclease has both exo- and endonucleolytic activities.