Bacteriophage phi29 terminal protein: its association with the 5' termini of the phi29 genome

Abstract

The location of the protein bound to bacteriophage .vphi.29 DNA was studied with restriction endonucleases, exonucleases and polynucleotide kinase. The protein is invariably associated with the 2 terminal DNA fragments generated by restriction endonucleases. The .vphi.29 DNA prepared with or without proteinase K treatment is resistant to the action of the 5''-terminal-specific exonucleases, .lambda.-[phage]-exonuclease and [phage] T7 exonuclease. The .vphi.29 DNA is also inaccessible to phosphorylation by polynucleotide kinase even after treatment with alkaline phosphatase. The .vphi.29 DNA is sensitive to exonuclease III, and the 3'' termini of the DNA can be labeled by incubating with .alpha.-[32P]ATP and terminal deoxynucleotidyl transferase. The protein remains associated with the .vphi.29 DNA after treatment with various chaotropic agents, including 8 M urea, 6 M guanidine-hydrochloride, 4 M sodium perchlorate, 2 M sodium thiocyanate and 2 M LiCl. The protein is apparently linked covalently to the 5'' termini of the .vphi.29 DNA.