An autophosphorylating but not transphosphorylating activity is associated with the unique N terminus of the herpes simplex virus type 1 ribonucleotide reductase large subunit.
We report on a protein kinase function encoded by the unique N terminus of the herpes simplex virus type 1 (HSV-1) ribonucleotide reductase large subunit (R1). R1 expressed in Escherichia coli exhibited autophosphorylation activity in a reaction which depended on the presence of the unique N terminus. When the N terminus was separately expressed in E. coli and partially purified, a similar autophosphorylation reaction was observed. Importantly, transphosphorylation of histones and of proteins in HSV-1-infected cell extracts was also observed with purified R1 and with truncated R1 mutants in which most of the N terminus was deleted. Ion-exchange chromatography was used to separate the autophosphorylating activity of the N terminus from the transphosphorylating activity of an E. coli contaminant protein kinase. We propose a putative function for this activity of the HSV-1 R1 N terminus during the immediate-early phase of virus replication.
Conner
J
J
Institute of Virology, University of Glasgow, United Kingdom.
Cooper
J
J
Furlong
J
J
Clements
J B
JB
D000255:Adenosine Triphosphate / Q000378:metabolism; D001345:Autoradiography; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D046911:Macromolecular Substances; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D012264:Ribonucleotide Reductases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017384:Sequence Deletion; D018139:Simplexvirus / Q000201:enzymology*
D046911:Macromolecular Substances; D010761:Phosphorus Radioisotopes; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D012264:Ribonucleotide Reductases