ADENOVIRUS PROTEIN-PROTEIN INTERACTIONS - HEXON AND PROTEIN-VI

A variety of mastadenoviruses were denatured, their polypeptides separ ated by electrophoresis on SDS-polyacrylamide gels and transferred to nitrocellulose. The immobilized polypeptides were washed, incubated wi th buffers containing herons from human adenoviruses (Ad) types 2, 5 a nd 12 and the location of bound herons was detected with anti-hexon an tibodies. It was found that herons from any of the three human adenovi rus types bound to protein VI from all the mastadenoviruses examined. Furthermore we found that hexon-VI binding was significantly greater t han the interaction between hexon and the precursor to VI, pVI. This b inding was susceptible to detergents and to changes in pH or salt conc entration. A rabbit polyclonal antibody was raised against a recombina nt protein derived from the middle third of pVI from Ad2 and was used to quantify the difference in binding and to demonstrate the presence of a single intermediate (designated iVI) in the processing of pVI to VI. The affinity between iVI and hexon was considerably greater in our assay than that of pVI but was less than that between hexon and VI. A complementary binding of recombinant iVI to immobilized herons was al so demonstrated. This latter interaction, however, was only observed w hen hexon preparations were not boiled prior to electrophoresis, subst antiating the proposition that the recognition motif on the hexon was conformation-dependent. These results are discussed in the context of understanding further the molecular basis of protein-protein interacti ons between the structural proteins of adenoviruses and the factors in volved in virion maturation.