The carboxy-terminal part of the NS 3 protein of the West Nile flavivirus can be isolated as a soluble protein after proteolytic cleavage and represents an RNA-stimulated NTPase

Virology. 1991 Oct;184(2):707-15. doi: 10.1016/0042-6822(91)90440-m.


Recently it has been reported that a membrane fraction can be isolated from West Nile virus-infected BHK cells which contains the viral nonstructural (NS) proteins as major constituents (Wengler et al., 1990). In this report we show that treatment of these membranes with subtilisin releases the carboxy-terminal segment of the NS 3 protein as a soluble protein of about 50 kDa apparent molecular weight. This molecule, which is called the p50-S protein, can be purified by standard chromatographic procedures. The p50-S protein binds to poly(A) and apparently represents a nucleoside triphosphatase which is stimulated in the presence of ssRNA molecules. The data represent experimental support for the predicted role of this segment of the NS 3 protein as an RNA helicase. Some properties of the p50-S protein are described and a possible function of this protein segment during RNA synthesis is discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Capsid / chemistry*
  • Capsid / isolation & purification
  • Capsid / metabolism
  • Enzyme Activation
  • Membrane Proteins / chemistry
  • Membrane Proteins / isolation & purification
  • Membrane Proteins / metabolism
  • Molecular Sequence Data
  • Molecular Weight
  • Nucleoside-Triphosphatase
  • Peptide Fragments
  • Phosphoric Monoester Hydrolases / chemistry*
  • Phosphoric Monoester Hydrolases / metabolism
  • RNA / pharmacology
  • RNA Helicases
  • RNA Nucleotidyltransferases / chemistry
  • RNA Nucleotidyltransferases / metabolism
  • Solubility
  • Subtilisins / pharmacology
  • Viral Core Proteins / chemistry*
  • Viral Core Proteins / isolation & purification
  • Viral Core Proteins / metabolism
  • Viral Nonstructural Proteins
  • West Nile virus / analysis*


  • Membrane Proteins
  • Peptide Fragments
  • Viral Core Proteins
  • Viral Nonstructural Proteins
  • RNA
  • RNA Nucleotidyltransferases
  • Phosphoric Monoester Hydrolases
  • Subtilisins
  • Nucleoside-Triphosphatase
  • RNA Helicases