The infectivity of adenovirus 5 DNA-protein complex

Adenovirus 5 DNA-protein complexes were prepared by treating virions with 4 M guanidinium chloride and resolving the faster sedimenting viral DNA from released capsid protein. These complexes were characterized by both gel electrophoresis and electron microscopy. After dialysis into saline buffer, approximately one-half of the viral DNA-protein complex was aggregated by association at its termini into conformations other than linear monomer length duplex molecules. However, the monomer length linear molecules in the viral DNA-protein complex sample also have protein attached to both of their termini: These linear molecules are resistant to digestion by a pressessive nuclease, adenosine triphosphate-dependent deoxyribonuclease, that requires a free terminus for activity, while Pronase-treated adenovirus DNA is susceptible to digestion, and the restriction endonuclease cleavage fragments from both ends of the viral DNA-protein complex migrate at an anomalous rate during electrophoresis in an agarose gel. As the infectivity of Ad5 DNA is exceptionally low, the infectivity of the DNA-protein complex was tested using the calcium technique for transfection. The efficiency of transfection with the Ad5 DNA-protein complex is about 100-fold higher than that of Pronase-treated Ad5 DNA.