[The type of covalent bond in a natural complex of the bacteriophage phi X 174 protein A* and nucleotides].

The 32P-labelled A* protein has been isolated from E. coli cells infected by phage phi X174 in the presence of [32P]orthophosphate. The snake venom phosphodiesterase treatment of the [32P]peptides obtained by the pronase digestion of the protein has revealed a phosphodiester bond between the protein and a nucleotide material of A, G base composition. The hydrolysis of nucleotide-peptides with a mixture of concentrated HCl and CF3COOH has yielded 4'O-phosphotyrosine.