The amino acid sequence of murine p53 determined from a c-DNA clone

A c-DNA clone containing the complete sequence information for the murine p53 protein, from embryonal carcinoma cells, has been isolated. The nucleotide sequence of this clone reveals an open reading frame encoding a protein of 390 amino acids with a molecular weight of 43,364 Da. The NH₂-terminal domain of this protein is acidic whereas the carboxyl terminus is rich in basic amino acid residues. These terminal domains are separated by a proline-rich, hydrophobic run of amino acids. Proline comprises approximately 10% of the total amino acid residues. Two tryptic peptides, derived from p53 protein radiolabeled with either methionine or proline, were purified and the position of these labeled residues in the peptide was determined. The positions of three methionine and five proline residues in these two peptides matched the amino acid sequence of the predicted open reading frame determined from the c-DNA clone.