The carboxy-terminal domain of Sendai virus nucleocapsid protein is involved in complex formation between phosphoprotein and nucleocapsid-like particles.
The replicative unit of Sendai virus, the nucleocapsid, is composed of the viral genomic RNA and the viral proteins NP, P, and L. P and L proteins form a polymerase complex and are associated with the nucleocapsid core (NP/RNA complex). The NP protein has recently been shown to be composed of two domains. While the amino-terminal domain I encapsidates RNA and gives rise to the characteristic helical nucleocapsid structure, the precise function of the carboxy-terminal domain II remained unclear. It was however supposed to be involved in binding the polymerase complex. To test this hypothesis, we established a cosedimentation assay which detects complex formation between P protein and nucleocapsid-like (NC-like) particles. Four mutant NC-like particles all carrying amino acid deletions in domain II of the NP protein were tested. Complex formation was abolished after deletion of amino acids 426-497 or 456-524, while deletions of amino acids 400-415 or 414-439 had no influence on the interaction. The results indicate that domain II of NP protein is involved in binding P protein to nucleocapsids. The function and position of a putative P protein binding site in domain II are discussed.
Buchholz
C J
CJ
Abteilung für Virusforschung, Max-Planck-Institut für Biochemie, Martinsried, Germany.
Retzler
C
C
Homann
H E
HE
Neubert
W J
WJ
D000818:Animals; D002213:Capsid / Q000302:isolation & purification / Q000378:metabolism*; D002642:Chick Embryo; D010222:Parainfluenza Virus 1, Human / Q000737:chemistry*; D010750:Phosphoproteins / Q000378:metabolism*; D014758:Viral Core Proteins / Q000302:isolation & purification / Q000378:metabolism*
D010750:Phosphoproteins; D014758:Viral Core Proteins