title: Steady-state cleavage kinetics for dengue virus type 2 ns2b-ns3(pro) serine protease with synthetic peptides.
abstract: The N-terminal part of the NS3 protein from dengue virus contains a trypsin-like serine protease responsible for processing the nonstructural region of the viral polyprotein. Enzymatic activity of the NS2B-NS3(pro) precursor incorporating a full-length NS2B cofactor of dengue virus type 2 was examined by using synthetic dodecamer peptide substrates encompassing native cleavage sequences of the NS2A/NS2B, NS2B/NS3, NS3/NS4A and NS4B/NS5 polyprotein junctions. Cleavage of the dansylated substrates was monitored by a HPLC-based assay and kinetic parameters for K(1M), k(cat) and k(cat)/K(m) were obtained. The data presented here show that NS2B-NS3(pro) expressed in recombinant E. coli can be renatured to an active protease which reacts in the absence of microsomal membranes with all 4 substrate peptides, albeit the molecule does not exhibit autoproteolytic processing at the NS2B/NS3 site. A marked difference in cleavage efficiency was found for the NS2B/NS3 substrate and the remaining 3 peptides based on the NS2A/NS2B, NS3/NS4A and NS4A/NS5 cleavage sites.
authors.affiliation: Laboratory of Molecular Virology, Institute of Molecular Biology and Genetics, Mahidol University, Salaya Campus, Phutthamonthon No. 4 Rd., Nakornpathom 73170, Thailand.
authors.forename: Rabuesak
authors.initials: R
authors.lastname: Khumthong
authors.forename: Pornwarat
authors.initials: P
authors.lastname: Niyomrattanakit
authors.forename: Santad
authors.initials: S
authors.lastname: Chanprapaph
authors.forename: Chanan
authors.initials: C
authors.lastname: Angsuthanasombat
authors.forename: Sakol
authors.initials: S
authors.lastname: Panyim
authors.forename: Gerd
authors.initials: G
authors.lastname: Katzenmeier
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003716:Dengue Virus / Q000201:enzymology* / Q000235:genetics; D004792:Enzyme Precursors / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D020365:RNA Helicases; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D004792:Enzyme Precursors; D009842:Oligopeptides; D020365:RNA Helicases; D011994:Recombinant Proteins; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C080102:NS2B protein, flavivirus; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases