Internal proteolysis of the NS3 protein specified by dengue virus 2.
The NS3 protein of flaviviruses is a multifunctional polypeptide required for virus replication. Enzymic activities that have been demonstrated or predicted from the presence of sequence motifs include protease, NTPase, helicase and RNA triphosphatase. Both full-length and truncated forms of NS3 have been identified in infected cells. To examine internal cleavage of the NS3 protein of dengue virus 2 (DEN-2), infected cells or COS cells transfected with cDNA encoding NS2B/3 were radiolabelled and immunoprecipitated with antiserum against NS3 or hyperimmune mouse ascitic fluid. The polypeptides detected were NS2B/3 (Mr 83000), NS3 (Mr 69000), NS3' (Mr 50000) and NS3" (Mr 19000). The latter polypeptide has not been previously identified. For DEN-2, it has been proposed that NS3' results from cleavage at the site ...R457R / GR460... within an RNA helicase sequence motif of NS3. Our results demonstrated that cleavage occurred at this site, and that prior cleavage between NS2B/NS3 was not necessary.
Teo
K F
KF
Department of Microbiology, Monash University, Clayton, Victoria, Australia.
Wright
P J
PJ
D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002522:Chlorocebus aethiops; D018076:DNA, Complementary; D003716:Dengue Virus / Q000201:enzymology* / Q000235:genetics; D004926:Escherichia coli; D051379:Mice; D011233:Precipitin Tests; D020365:RNA Helicases; D012697:Serine Endopeptidases; D014162:Transfection; D014709:Vero Cells; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D018076:DNA, Complementary; D020365:RNA Helicases; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases