InterPro : IPR004109

Name  Peptidase S29, hepatitus C polyprotein NS3 Short Name  Peptidase_S29
Type  Domain Description  Proteolytic enzymes that exploit serine in their catalytic activity are ubiquitous, being found in viruses, bacteria and eukaryotes []. They include a wide range of peptidase activity, including exopeptidase, endopeptidase, oligopeptidase and omega-peptidase activity. Many families of serine protease have been identified, these being grouped into clans on the basis of structural similarity and other functional evidence []. Structures are known for members of the clans and the structures indicate that some appear to be totally unrelated, suggesting different evolutionary origins for the serine peptidases [].Not withstanding their different evolutionary origins, there are similarities in the reaction mechanisms of several peptidases. Chymotrypsin, subtilisin and carboxypeptidase C have a catalytic triad of serine, aspartate and histidine in common: serine acts as a nucleophile, aspartate as an electrophile, and histidine as a base []. The geometric orientations of the catalytic residues are similar between families, despite different protein folds []. The linear arrangements of the catalytic residues commonly reflect clan relationships. For example the catalytic triad in the chymotrypsin clan (PA) is ordered HDS, but is ordered DHS in the subtilisin clan (SB) and SDH in the carboxypeptidase clan (SC) [, ].This signature identifies the Hepatitis C virusNS3 protein as a serine protease which belongs to MEROPS peptidase family S29 (hepacivirin family, clan PA(S)), which has a trypsin-like fold. The non-structural (NS) protein NS3 is one of the NS proteins involved in replication of the HCV genome. The NS2 proteinase (), a zinc-dependent enzyme, performs a single proteolytic cut to release the N terminus of NS3. The action of NS3 proteinase (NS3P), which resides in the N-terminal one-third of the NS3 protein, then yields all remaining non-structural proteins. The C-terminal two-thirds of the NS3 protein contain a helicase. The functional relationship between the proteinase and helicase domains is unknown. NS3 has a structural zinc-binding site and requires cofactor NS4. It has been suggested that the NS3 serine protease of hepatitus C is involved in cell transformation and that the ability to transform requires an active enzyme [].

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

0 Found In

1 Parent Features

Id Name Short Name Type
IPR009003 Trypsin-like cysteine/serine peptidase domain Trypsin-like_Pept_dom Domain

3 Publications

First Author Title Year Journal Volume Pages
Rawlings ND Evolutionary families of peptidases. 1993 Biochem J 290 ( Pt 1) 205-18
Rawlings ND Families of serine peptidases. 1994 Methods Enzymol 244 19-61
Zemel R Cell transformation induced by hepatitis C virus NS3 serine protease. 2001 J Viral Hepat 8 96-102

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)