Formation of a covalent complex between the 80,000-dalton adenovirus terminal protein and 5'-dCMP in vitro.

An in vitro adenovirus DNA replication system catalyzed the formation of a covalent complex between an 80,000-dalton protein and 5'-dCMP in the presence of [alpha-32P-dCTP, MgCl2, ATP, and adenovirus (Ad) DNA with a protein covalently bound to the 5' end of each strand (Ad DNA-prot). The requirement for Ad DNA-prot in this reaction was similar to that for in vitro DNA replication. When dATP, dTTP, and the 2',3'-dideoxynucleoside triphosphate (ddNTP) ddGTP were included in the reaction mixture, an elongated complex was detected, which consisted of an 80,000-dalton protein bound to a 26-base oligonucleotide. Formation of the elongated product, but not of the protein-dCMP complex, was inhibited by ddATP, ddCTP, or ddTTP. The requirements for formation of the protein-dCMP complex, the nature of the linkage between protein and dCMP, the size of the protein, and the existence of elongated forms indicated that the protein associated with the complex was identical to the 80,000-dalton Ad terminal protein found on replicating DNA molecules as described by Challberg et al. [Challberg, M. D., Desiderio, S. V. & Kelly, T. J., Jr. (1980) Proc. Natl. Acad. Sci. USA 77, 5105-5109].