BACTERIAL EXPRESSION OF HUMAN RESPIRATORY SYNCYTIAL VIRAL PHOSPHOPROTEIN-P AND IDENTIFICATION OF SER(237) THE SITE OF PHOSPHORYLATION BY CELLULAR CASEIN KINASE-II

The phosphoprotein P gene of human respiratory syncytial virus has bee n cloned and the protein expressed in Escherichia coli. The expressed protein was soluble, unphosphorylated, and constituted similar to 10% of the total bacterial protein. Electrophoretic and antigenic analyses demonstrated the identity of the recombinant protein with viral P pro tein and P protein synthesized in reticulocyte lysates. Purified recom binant P protein was efficiently phosphorylated in vitro by purified n ative as well as recombinant casein kinase II (CKII) or by the CKII ac tivity in uninfected cell extracts. Through deletions and site-directe d mutagenesis, the site of CKII phosphorylation was mapped to a single serine residue (Ser(237)) near the C-terminal end of the P protein. ( C) 1994 Academic Press, Inc.