Yeast ribosome core particles deficient in acidic proteins L44 and L45 and their activity in reconstitution...

The yeast ribosome core particles partly depleted of acidic proteins, L44 and L45, were isolated and their activity was examined using a highly purified protein synthesizing system. It was shown that both the phenylalanine polymerization reaction and the elongation factor 2-dependent GTP hydrolysis were stimulated by the addition of the extracted acidic protein fraction. The results obtained clearly indicate a functional role of these proteins in the elongation step of eukaryotic protein synthesis. The essential parameters of ribosome reconstitution experiments are discussed.