Title: Purification, primary structure, and homology relationships of a chloroplast ribosomal protein
Abstract: A chloroplast ribosomal protein that showed immunological homology to Escherichia coli ribosomal protein L12 was purified from spinach ( Spinacia oleracea ) leaves and its primary structure was determined by manual micro Edman degradation. The protein is composed of 130 amino acid residues and has M r 13,576. It shows structural features characteristic of the L12 proteins of eubacterial 70S ribosomes (e.g., identical amino acid residues in about 50% of the sequence) but no apparent homology to the L12-type proteins of eukaryotic cytoplasmic 80S ribosomes. The homology to eubacterial proteins is highest in the COOH-terminal region (70%) and low in the NH 2 -terminal region (<20%).