Deletion mapping of the potyviral helper component-proteinase reveals two regions involved in RNA binding.
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.
Urcuqui-Inchima
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S
Institut Jacques Monod, 2 place Jussieu-Tour 43, Paris Cedex 05, 75251, France.
Maia
I G
IG
Arruda
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P
Haenni
A L
AL
Bernardi
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F
D018528:ATP-Binding Cassette Transporters; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D017354:Point Mutation; D017800:Potyvirus / Q000201:enzymology* / Q000235:genetics; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D015347:RNA Probes; D012367:RNA, Viral / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011198:Solanum tuberosum / Q000821:virology; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D009838:Oligodeoxyribonucleotides; D015347:RNA Probes; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; C461599:maltose transport system, E coli; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus