Modification of the cleavage activation of the influenza virus hemagglutinin by site-specific mutagenesis.
Factors determining cleavability of influenza virus hemagglutinin which is activated by ubiquitous cellular endoproteases were analysed by carrying out site-directed mutagenesis on the cloned hemaglutinin genes of strains A/FPV/Rostock/34 (subtype H7) and A/Port Chalmers/1/73 (subtype H3). Substitutions at the cleavage site of the H7 hemagglutinin indicate that the tetrapeptide Arg-X-Lys/Arg-Arg is the minimal consensus sequence recognized by the ubiquitous proteases. The H3 hemagglutinin also became susceptible to these enzymes, when additional arginines were inserted at the cleavage site. Three arginines were sufficient, when the carbohydrate was removed, whereas four additional arginines are needed when this carbohydrate was present, indicating that the accessibility of the cleavage motif is important for the protease. The appropriate localization of the basic cleavage motif within the amino acid sequence and the spatial structure of the hemagglutinin precursor is an additional prerequisite for cleavage.
Institut für Virologie, Philipps-Universität Marburg, Germany.
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Garten
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Vey
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Ohuchi
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Ohuchi
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Klenk
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002459:Cell Fusion; D002460:Cell Line; D010450:Endopeptidases / Q000378:metabolism*; D005814:Genes, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000235:genetics* / Q000378:metabolism; D009980:Influenza A virus / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000235:genetics
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D014759:Viral Envelope Proteins; D010450:Endopeptidases