The primary structure of rat ribosomal proteins: the amino acid sequences of L27a and L28 and corrections in the sequences of S4 and S12.

The amino acid sequences of rat ribosomal proteins L27a and L28 were deduced from the sequences of nucleotides in recombinant cDNAs and confirmed from the NH2-terminal amino acid sequences of the proteins. L27a contains 147 amino acids (the NH2-terminal methionine is removed after translation of the mRNA) and has a molecular weight of 16 476. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 18-22 copies of the L27a gene. The mRNA for the protein is about 600 nucleotides in length. L27a is homologous to mouse L27a (there are 3 amino acid changes) and to yeast L29. Rat ribosomal protein L28 has 136 amino acids (its NH2-terminal methionine is also processed after translation) and has a molecular weight of 15 707. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 9 or 10 copies of the L28 gene. The mRNA for the protein is about 640 nucleotides in length. L28 contains a possible internal duplication of 9 residues. Corrections are recorded in the sequences reported before for rat ribosomal proteins S4 and S12.