Proteolytic processing of the proteins translated from the bottom component RNA of cowpea mosaic virus. The primary and secondary cleavage reactions.

This is the authors' abstract. We don't add key points for this paper.

The products of translation of cowpea mosaic virus B-RNA in rabbit reticulocyte lysates are proteolytically cleaved to form a specific set of proteins. The primary cleavage occurs as nascent peptide chains elongate to a size of about 150 kilodaltons yielding a 32K protein and, upon chain completion, a 170K protein. This cleavage reaction is inhibited by 3 mM iodoacetamide. The 170K protein, in turn, is cleaved to yield either of two pairs of proteins, a 110K and 60K pair or a 87K and 84K pair. The reaction for forming the 110K-60K pair is sensitive to dilution, indicating that a free factor is involved. The reaction for forming the 87K-84K pair, on the other hand, is not affected by diluting the lysate reaction mixture with buffer even to 200-fold, indicating that the reaction is autolytic. Formation of the 110K-60K pair, but not the 87K-84K pair, is inhibited by 2 mM zinc chloride. Translational mapping data indicate that the 87K and 60K proteins are derived from the NH2-terminal side of the 170K protein.