Separate domains of Sendai virus P protein are required for binding to viral nucleocapsids.
The role of Sendai virus P protein in viral RNA synthesis involves association with the nucleocapsid template. There is evidence that the carboxyl-terminal region of P protein is responsible for this association (K. W. Ryan and D. W. Kingsbury, 1988, Virology 167, 106-112). To define the P protein sequences involved more precisely, deletions were generated in a cDNA clone of the P gene. Proteins synthesized in vitro from these altered P genes were mixed with extracts from infected cells to determine if they could attach to nucleocapsids. Under conditions where full-size P protein was able to bind, a protein comprising the 95 carboxyl-terminal residues of P protein (Sendai virus X protein) did not bind. This indicated that other P protein residues were required, in addition to the 95 residues at the carboxyl-terminal end. To locate these other residues, P genes were constructed with overlapping deletions of sequences encoding the carboxyl-terminal 40% of the protein. Analysis of these deleted proteins revealed that the necessary residues were in two separate binding domains, amino acids 345 to 412 and 479 to 568 (the carboxyl-terminus). Deletion of the 66 residues between these regions did not affect attachment. Therefore, the formation of a functional binding site requires residues within two separate regions of P protein.
Ryan
K W
KW
Department of Virology and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38101.
Portner
A
A
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001665:Binding Sites; D002213:Capsid / Q000378:metabolism*; D002872:Chromosome Deletion; D010222:Parainfluenza Virus 1, Human / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D013329:Structure-Activity Relationship; D014758:Viral Core Proteins / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D000596:Amino Acids; C055859:P protein, Sendai virus; D010750:Phosphoproteins; D014758:Viral Core Proteins; D014764:Viral Proteins