A transcriptionally controlled trans-processing assay: putative identification of a vaccinia virus-encoded proteinase which cleaves precursor protein P25K.
Vaccinia virus maturation into infectious particles appears to be dependent on the proteolytic processing of at least five viral proteins, each containing a conserved AG*X cleavage motif and each requiring proper association with the previrion particle. To identify the responsible proteinase, a transcriptionally controlled trans-processing assay was developed to monitor cleavage at the permissive AG*S site of the P25K core protein precursor. This assay led to the putative identification of a VV proteinase encoded by open reading frame G1L. The predicted protein contains an HXXEH sequence which is a direct inversion of the active site consensus sequence present in thermolysin and other metalloendopeptidases. Site-directed mutation of this consensus sequence suggests that the G1L protein may be a novel, virus-encoded metalloendoproteinase, although confirmation of this activity must await the development of a suitable cell-free processing assay.
Whitehead
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Department of Microbiology, Oregon State University, Corvallis 97331-3804.
Hruby
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DE
D000595:Amino Acid Sequence; D003561:Cytarabine / Q000494:pharmacology; D008666:Metalloendopeptidases / Q000032:analysis* / Q000737:chemistry / Q000502:physiology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011498:Protein Precursors / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014616:Vaccinia virus / Q000201:enzymology* / Q000235:genetics; D014758:Viral Core Proteins / Q000378:metabolism*
D011498:Protein Precursors; D014758:Viral Core Proteins; D003561:Cytarabine; D008666:Metalloendopeptidases