MESSENGER-DEPENDENT ACTION OF THE POKEWEED ANTIVIRAL PROTEIN AND FUSIDIC ACID ON IN-VITRO VICIA-SATIVA L TRANSLATION

Plant ribosome sensitivity to either pokeweed antiviral protein (PAP) or fusidic acid has been investigated using a highly coupled translati on system obtained from Vicia sativa L., a plant that lacks ribosome-i nactivating protein activity. Protein synthesis directed by endogenous messengers was more sensitive to PAP than synthesis of polyphenylalan ine directed by polyuridylic acid. Conversely, the effects of fusidic acid were the highest in polyphenylalanine synthesis. Additionally, th e concentration of magnesium ions during translation also played a det erminant role in the extent of inhibition by both PAP and fusidic acid . The effects seem to be exerted on the interaction of the translation al elongation factor 2 with the ribosome.