NP:P and NP:V interactions of the paramyxovirus simian virus 5 examined using a novel protein:protein capture assay.
Using recombinant proteins extracted from mammalian cells, in a novel protein:protein binding assay, direct interaction of the nucleoprotein (NP) of simian virus 5 with the phosphoprotein (P) and V protein (V) was demonstrated. The amount of NP bound by V was found to be significantly less than that bound by P. Furthermore, preabsorption of NP with P removed the fraction of NP that could be bound by V, but preabsorption of NP with V did not remove all the NP that could be bound by P. These results suggested that V bound a subpopulation of the NP recognised by P. Further analysis revealed that P bound both soluble and homopolymeric forms of NP, while V bound only the soluble form; thus demonstrating that the binding sites on P and V, for soluble NP, are located within the N-terminal domain common to both P and V proteins. A monoclonal antibody, which recognised an epitope in the unique C-terminus of P, blocked the binding of P to polymeric NP but not to soluble NP. These results also suggest that there are two binding sites on NP for P, the site that interacts with the P/V common domain being either hidden or conformationally altered in polymeric NP.
Randall
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RE
School of Biological and Medical Sciences, University of St. Andrews, Fife, Scotland.
Bermingham
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D000818:Animals; D001665:Binding Sites; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins; D019085:Fluorescent Antibody Technique, Direct; D010750:Phosphoproteins; D011485:Protein Binding; D018108:Respirovirus / Q000378:metabolism*; D013552:Swine; D014764:Viral Proteins / Q000378:metabolism*
D036022:Capsid Proteins; C055859:P protein, Sendai virus; D010750:Phosphoproteins; D014764:Viral Proteins; C075566:nucleocapsid protein, simian virus 5; C074576:V protein, Porcine rubulavirus