Effect of proteolytic digestion on the function of vesicular stomatitis virus ribonucleoprotein complex.

ABSTRACT

The nucleocapsid protein (49 Kd) of vesicular stomatitis virus is tightly bound to the genome rendering the latter transcriptionally competent. Controlled digestion with chymotrypsin removed a 12 Kd peptide from the complex. The resulting complex failed to serve as template for genome transcription in vitro when the polymerase components L and NS proteins were added. A template-associated protein kinase activity was also lost upon chymotrypsin treatment. However, the cleaved nucleocapsid protein (37 Kd) was still capable of binding tightly with the genome template and retained the epitope recognized by a monoclonal antibody. These results suggest that the nucleocapsid protein possesses separate domains that mediate binding to polymerase complex and maintain the structural integrity of the template.