Herpes simplex virus type 1 DNase: Functional analysis of the enzyme expressed by recombinant baculovirus

Herpes simplex virus type 1 DNase (HSV-1 DNase) was expressed in insect cel ls by recombinant baculovirus (NPVUL12) and purified by a combination of an ionic exchanger chromatography ana gel filtration. Two polypeptides or 85 a nd 75 kD, whose ratio varied during purification, were induced 24 h after i nfection. The 75-kD protein was isolated and shown to possess catalytic act ivity. Gel filtration analysts indicated that the active form of the enzyme at an ionic strength of I = 0.3 is a dimeric protein with an apparent mole cular weight of 130,000. The recombinant enzyme exhibited the overall chara cteristics of ity. Gel filtration analysis indicated that the active form o f the enzyme at an Herpes simplex virus type 1 DNase (HSV-1 DNase) was expr essed in insect cells by recombinant baculovirus (NPVUL12) and purified by a combination of anionic exchanger chromatography and gel filtration. Two p olypeptides of the native enzyme such as 5'-3' exonuclease and endonuclease activities with a preferred degradation of DNA. In the absence of extraneo usly added Mg2+, the enzyme was capable of removing mononucleotides from 5' -end-labeled DNA, but not from RNA and 3'-end-labeled DNA. The peculiar mec hanism of double-strand DNA degradation suggests a specific role of HSV-1 D Nase in DNA recombination processes during viral replication.