Ultrastructural localization of L and NS enzyme subunits on vesicular stomatitis virus RNPs using gold sphere-staphylococcal protein A-monospecific IgG conjugates

Colloidal gold spheres were coated with staphylococcal protein A and were used to determine the location of NS and L proteins on vesicular stomatitis virus (VSV) ribonucleoprotein (RNP) complexes using monospecific anti-NS and anti-L IgG preparations. Conjugates using either anti-NS or anti-L demonstrated that these enzyme subunits were uniformly distributed along the entire length of the RNP complex. Under saturating conditions of IgG concentrations, it was observed that there were at least 60–70 molecules of NS protein and 30–35 molecules of L protein labeled per RNP complex.