title: Murine leukemia virus protease is encoded by the gag-pol gene and is synthesized through suppression of an amber termination codon.
abstract: We have purified from Moloney murine leukemia virus (Mo-MuLV) a protease that has the capacity of accurately cleaving the polyprotein precursor Pr65gag into the mature viral structural proteins. Both the NH2- and COOH-terminal amino acid sequences have been determined and aligned with the amino acid sequence deduced from the DNA sequence of Mo-MuLV by other workers. The results show that: (i) the protease is located at the 5' end of the pol gene, and the first four amino acids are overlapped with the 3' end of the gag gene; (ii) the fifth amino acid residue is glutamine, which is inserted by suppression of the UAG termination codon at the gag-pol junction; and (iii) the protease is composed of 125 amino acids with calculated Mr = 13,315, and the COOH terminus of the protease is adjacent to the NH2 terminus of reverse transcriptase. The map order of the gag-pol gene is proposed to be 5'-p15-p12-p30-p10-protease-reverse transcriptase-endonuclease-3'.
mesh_terms: D000595:Amino Acid Sequence; D003062:Codon / Q000235:genetics; D005814:Genes, Viral; D008979:Moloney murine leukemia virus / Q000201:enzymology / Q000235:genetics*; D010447:Peptide Hydrolases / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D014176:Protein Biosynthesis; D013489:Suppression, Genetic
chemical_list: D003062:Codon; D010447:Peptide Hydrolases