The primary structure of rat ribosomal protein L23a. The application of homology search to the identification of genes for mammalian and yeast ribosomal proteins and a correlation of rat and yeast ribosomal proteins.

The amino acid sequence of the rat 60 S ribosomal subunit protein L23a was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein L23a has 156 amino acids and a molecular weight of 17,684. Hybridization of the L23a cDNA to digests of nuclear DNA suggests that there are 18-20 copies of the L23a gene. The mRNA for the protein is about 600 nucleotides in length. Rat L23a is related to the yeast Saccharomyces cerevisiae L25, to the archaebacterial Methanococcus vannielii L23, to eubacterial Escherichia coli L23, and to other members of the L23 family of ribosomal proteins. A novel application of a routine homology search procedure was employed to identify a nucleotide sequence that could be used to design an oligodeoxynucleotide probe to screen a library for a cDNA that encodes rat L23a; this same procedure uncovered a number of previously unidentified genes for yeast ribosomal proteins in the GenBank DNA data base. In a correlation of rat and yeast ribosomal proteins 48 pairs are shown to be related.