CATH Classification

Domain Context

CATH Clusters

Superfamily Trypsin-like serine proteases
Functional Family Genome polyprotein

Enzyme Information
RNA helicase.
based on mapping to UniProt P26663
ATP + H(2)O = ADP + phosphate.
-!- RNA helicases utilize the energy from ATP hydrolysis to unwind RNA. -!- Some of them unwind RNA with a 3' to 5' polarity, other show 5' to 3' polarity. -!- Some helicases unwind DNA as well as RNA. -!- May be identical with EC (DNA helicase).
Cysteine endopeptidases.
based on mapping to UniProt P26663
based on mapping to UniProt P26663
Hydrolysis of four peptide bonds in the viral precursor polyprotein, commonly with Asp or Glu in the P6 position, Cys or Thr in P1 and Ser or Ala in P1'.
-!- Encoded by the genome of the viruses of the hepatitis C group, and contributes to the maturation of the precursor polyproteins. -!- The enzyme is greatly activated by binding of the 54-residue NS4A 'cofactor' protein also derived from the viral polyprotein. -!- Belongs to peptidase family S29.
RNA-directed RNA polymerase.
based on mapping to UniProt P26663
Nucleoside triphosphate + RNA(n) = diphosphate + RNA(n+1).
-!- Catalyzes RNA-template-directed extension of the 3'-end of an RNA strand by one nucleotide at a time. -!- Can initiate a chain de novo. -!- See also EC
Nucleoside-triphosphate phosphatase.
based on mapping to UniProt P26663
NTP + H(2)O = NDP + phosphate.
-!- The enzyme is found in eukaryotes and thermophilic bacteria, but appears to be absent from mesophilic bacteria. -!- Also hydrolyzes nucleoside diphosphates, thiamine diphosphate and FAD. -!- The enzyme from the plant Pisum sativum (garden pea) is regulated by calmodulin.

UniProtKB Entries (1)

Hepatitis C virus (isolate BK)
Genome polyprotein

PDB Structure

External Links
Organism Escherichia
Primary Citation
The solution structure of the N-terminal proteinase domain of the hepatitis C virus (HCV) NS3 protein provides new insights into its activation and catalytic mechanism.
Barbato, G., Cicero, D.O., Nardi, M.C., Steinkuhler, C., Cortese, R., De Francesco, R., Bazzo, R.