Nucleoside diphosphate kinase activity in purified cores of vesicular stomatitis virus.

Purified cores of vesicular stomatitis virus contain an enzymatic activity that converts GDP, UDP, and CDP into their corresponding triphosphates using ATP as the phosphate donor. Thus, the virion-associated RNA polymerase can synthesize mRNA normally in vitro even when one of the ribonucleoside triphosphates is replaced by its corresponding diphosphate. RNA synthesis does not proceed if ATP is replaced by ADP. Similarly RNA synthesis is impaired if CDP and UDP are present in the same reaction. The role of the nucleoside diphosphate kinase (NDP kinase, EC 2.7.4.6) in vesicular stomatitis virus mRNA synthesis in vitro is discussed.