Protein kinase of bacteriophage T7 induces the phosphorylation of only a small number of proteins in the infected cell.
Bacteriophage T7 expresses a serine/threonine-specific, cAMP-independent protein kinase activity encoded by the early gene 0.7. The phosphoproteins specifically resulting from gp0.7 protein kinase expression in T7-infected Escherichia coli have been examined by one-dimensional, SDS-polyacrylamide gel electrophoresis. Only seven major, stable phosphoproteins dependent on gp0.7 protein kinase expression are observed. Two of the gp0.7 protein kinase-specific phosphoproteins observed have been previously identified: the beta' subunit of RNA polymerase and the RNA processing enzyme RNase III. The gp0.7-catalyzed protein phosphorylation activity appears at 9-11 min postinfection at 30 degrees. The new phosphoproteins have a metabolic stability comparable to that of uninfected cell phosphoproteins. T7 protein kinase expression causes the phosphorylation of the same, limited set of proteins in B, C, or K strains of E. coli. Expression of the T3 and BA14 phage protein kinase activities also produces the same phosphoproteins.
Robertson
E S
ES
Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202.
Nicholson
A W
AW
D001426:Bacterial Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D010750:Phosphoproteins / Q000032:analysis*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D013604:T-Phages / Q000201:enzymology*; D013997:Time Factors
D001426:Bacterial Proteins; D010750:Phosphoproteins; D011494:Protein Kinases