title: DNA-independent ATPase activity of the Trichoplusia ni granulovirus DNA helicase.
abstract: DNA helicases of baculoviruses are essential for virus replication and have been implicated as molecular determinants of host range. Although these proteins contain seven motifs (I, Ia, II-VI) characteristic of DNA helicases, the two most important characteristics of helicases - duplex-DNA unwinding and ATPase activity - have not been demonstrated. In the present study, a recombinant putative DNA helicase (rP137) of Trichoplusia ni granulovirus (TnGV) was purified from insect cells infected with a recombinant Autographa californica multicapsid nucleopolyhedrovirus that overproduced rP137. The rP137 protein exhibited an intrinsic DNA-independent ATPase activity that required Mg(2+) as a co-factor, an activity that was reduced in the presence of TnGV and phage lambda DNAs. These results provide further evidence that baculovirus helicase genes encode proteins with biochemical properties similar to those of classical DNA helicases.
authors.affiliation: Graduate Program in Genetics and Department of Entomology, University of California, Riverside, CA 92521, USA. brian.federici@ucr.edu
authors.forename: D K
authors.initials: DK
authors.lastname: Bideshi
authors.forename: B A
authors.initials: BA
authors.lastname: Federici
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D016367:Baculoviridae / Q000201:enzymology*; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D009036:Moths / Q000821:virology; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C112407:P137 protein, Trichoplusia ni granulovirus; D014764:Viral Proteins; D004247:DNA; D000251:Adenosine Triphosphatases; D004265:DNA Helicases