Isolation and characterization of adenovirus core nucleoprotein subunits

Digestion of adenovirus type 2 (Ad2) or Ad5 cores with micrococcal nuclease generated four nucleoprotein species that could be resolved by electrophoresis in low-ionic-strength polyacrylamide gels: these nucleoproteins displayed mobilities equivalent to those of DNA fragments of 900 to 1,025, 775 to 850, 650 to 725, and 525 to 600 base pairs (bp) and thus were readily distinguishable from HeLa cell mononucleosomes. The DNA fragments associated with the core nucleoprotein species were more than 250 to 90 bp long. Nucleoproteins containing 150, 120, or 90 bp of DNA were the most stable. Polypeptide VII was associated with each of the nucleoprotein species liberated from Ad2 cores. These data suggest that polypeptide VII and viral DNA of 90 to 150 bp comprise the unit particle of the Ad2 or Ad5 core nucleoproteins.