Nucleic acid-binding properties of a bacterially expressed potato virus Y helper component-proteinase.
The potyvirus helper component-proteinase (HC-Pro) is a multifunctional protein previously reported to have affinity for polyribonucleotides. To investigate further the ability of HC-Pro to bind nucleic acids, the potato virus Y (PVY) LYE84 isolate HC-Pro gene was amplified, cloned in an Escherichia coli expression vector and sequenced. HC-Pro was expressed as a fusion with the maltose-binding protein and purified by affinity chromatography. Electrophoretic mobility-shift assays demonstrated that HC-Pro acts as a sequence non-specific RNA-binding protein and suggest that more than one molecule of protein was bound per molecule of RNA. The HC-Pro RNA-binding activity was stable in 400 mm-NaCl and temperature sensitive. The recombinant protein preferentially bound ssRNA over DNA or dsRNA and showed little, if any, affinity for poly(A). The possible implications of the RNA-binding activity of HC-Pro in potyvirus replication and movement are discussed.
Maia
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IG
Institut Jacques Monod, Paris, France.
Bernardi
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F
D001483:Base Sequence; D018076:DNA, Complementary / Q000737:chemistry; D010450:Endopeptidases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D008969:Molecular Sequence Data; D017800:Potyvirus / Q000737:chemistry*; D012313:RNA / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*
D018076:DNA, Complementary; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D012313:RNA; D010450:Endopeptidases