Abstract
The Potyvirus helper component-proteinase (HC-Pro) binds nonspecifically to single-stranded nucleic acids with a preference for RNA. To delineate the regions of the protein responsible for RNA binding, deletions were introduced into the full-length Potato potyvirus Y HC-Pro gene carried by an Escherichia coli expression vector. The corresponding proteins were expressed as fusions with the maltose-binding protein, purified, and assayed for their RNA-binding capacity. The results obtained by UV cross-linking and Northwestern blot assays demonstrated that the N- and C-terminal regions of HC-Pro are dispensable for RNA binding. They also revealed the presence of two independent RNA-binding domains (designated A and B) located in the central part of HC-Pro. Domain B appears to contain a ribonucleoprotein (RNP) motif typical of a large family of RNA-binding proteins involved in several cellular processes. The possibility that domain B consists of an RNP domain is discussed and suggests that HC-Pro could constitute the first example of a plant viral protein belonging to the RNP-containing family of proteins.
Copyright 2000 Academic Press.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP-Binding Cassette Transporters*
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Amino Acid Motifs
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Amino Acid Sequence
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cysteine Endopeptidases / chemistry*
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Cysteine Endopeptidases / genetics
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Cysteine Endopeptidases / metabolism*
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Escherichia coli Proteins*
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Gene Deletion
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Maltose-Binding Proteins
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Molecular Sequence Data
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Monosaccharide Transport Proteins*
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Oligodeoxyribonucleotides / chemistry
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Oligodeoxyribonucleotides / metabolism
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Point Mutation
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Potyvirus / enzymology*
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Potyvirus / genetics
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Protein Structure, Secondary
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Protein Structure, Tertiary
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RNA Probes
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RNA, Viral / metabolism*
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RNA-Binding Proteins / chemistry*
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / metabolism
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Solanum tuberosum / virology
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Viral Proteins / chemistry*
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Viral Proteins / genetics
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Viral Proteins / metabolism*
Substances
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ATP-Binding Cassette Transporters
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Carrier Proteins
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Escherichia coli Proteins
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Maltose-Binding Proteins
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Monosaccharide Transport Proteins
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Oligodeoxyribonucleotides
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RNA Probes
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RNA, Viral
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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Viral Proteins
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maltose transport system, E coli
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Cysteine Endopeptidases
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HC-Pro protein, potyvirus