Occurrence of a methylated protein in chloroplast ribosomes

A ribosomal protein of spinach chloroplast, previously shown to be immunologically homologous to Escherichia coli ribosomal protein L2, was purified by using gel filtration, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography separation. Methyl modification of proteins, whose occurrence in E. coli ribosomes is established, is present in chloroplast ribosomes as well. This and the additional significance of the amino acid sequence data reported in this paper are discussed.