J. Olvera et Ig. Wool, THE CARBOXYL EXTENSION OF A UBIQUITIN-LIKE PROTEIN IS RAT RIBOSOMAL-PROTEIN S30, The Journal of biological chemistry, 268(24), 1993, pp. 17967-17974
The amino acid sequence of the rat 40 S ribosomal subunit protein S30
was deduced from the sequence of nucleotides in a recombinant cDNA and
confirmed by the determination of the 18 residues at the NH2 terminus
of the protein. Unlike the majority of ribosomal proteins, which are
unprocessed primary products of the translation of their mRNAs, S30 is
formed by cleavage from a larger hybrid protein. The NH2-terminal pol
ypeptide has 38% identity with ubiquitin and contains the characterist
ic carboxyl-terminal Gly-Gly dipeptide of this family of proteins. S30
has 59 amino acids and the molecular weight is 6,643; the ubiquitin-l
ike sequence has 74 residues and the molecular weight is 7,634. The hy
brid protein is encoded in each of the 8-10 members of the family of r
at S30 genes; there is, however, only a single species of mRNA which c
ontains the sequences for both proteins. The coding sequence of the hy
brid protein occurs in the reverse polarity in the genome of the Finke
l-Biskis-Reilly murine sarcoma virus.