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119  structures 30  species 0  interactions 37  sequences 8  architectures

Family: Peptidase_S7 (PF00949)

Summary: Peptidase S7, Flavivirus NS3 serine protease

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Peptidase S7, Flavivirus NS3 serine protease Provide feedback

The viral genome is a positive strand RNA that encodes a single polyprotein precursor. Processing of the polyprotein precursor into mature proteins is carried out by the host signal peptidase and by NS3 serine protease, which requires NS2B (PF01002) as a cofactor [4].

Literature references

  1. Kapoor M, Zhang L, Ramachandra M, Kusukawa J, Ebner KE, Padmanabhan R; , J Biol Chem 1995;270:19100-19106.: Association between NS3 and NS5 proteins of dengue virus type 2 in the putative RNA replicase is linked to differential phosphorylation of NS5. PUBMED:7642575 EPMC:7642575

  2. Chambers TJ, Hahn CS, Galler R, Rice CM; , Annu Rev Microbiol 1990;44:649-688.: Flavivirus genome organization, expression, and replication. PUBMED:2174669 EPMC:2174669

  3. Koonin EV, Dolja VV; , Crit Rev Biochem Mol Biol 1993;28:375-430.: Evolution and taxonomy of positive-strand RNA viruses: implications of comparative analysis of amino acid sequences. PUBMED:8269709 EPMC:8269709

  4. Murthy HM, Clum S, Padmanabhan R; , J Biol Chem 1999;274:5573-5580.: Dengue virus NS3 serine protease. Crystal structure and insights into interaction of the active site with substrates by molecular modeling and structural analysis of mutational effects. PUBMED:10026173 EPMC:10026173

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001850

The viral genome of Flavivirus is a positive strand RNA that encodes a single polyprotein precursor. Processing of the polyprotein precursor into mature proteins is carried out by the host signal peptidase and by NS3 serine protease, which requires NS2B ( INTERPRO ) as a cofactor [ PUBMED:10026173 ].

Pathogenic members of the flavivirus family, including West Nile Virus (WNV) and Dengue Virus (DV), are growing global threats for which there are no specific treatments. The genome encodes three structural proteins found in the mature virion (C, prM, and E) and seven "nonstructural" (i.e., not part of the virion architecture) proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5). Full-length NS3 is a bifunctional protein. The N-terminal 175 residues comprise a chymotrypsin-like protease, while the C-terminal portion is a helicase. The NS2B protein, which is located in the polypeptide precursor immediately upstream of the NS3 protease domain, functions as the cofactor for NS3 protease. A 35-48 residue central portion is required for protease activity in vitro, while N- and C-terminal flanking hydrophobic regions are predicted to anchor the NS2B-NS3 complex into the host endoplasmic reticulum membrane. The two component flaviviral enzyme NS2B-NS3 cleaves the viral polyprotein precursor within the host cell, a process that is required for viral replication [ PUBMED:17400917 , PUBMED:19693793 , PUBMED:20042502 ]. The NS3 protease forms the MEROPS peptidase family S7 (flavivirin family), clan PA.

The NS3 protease has a classical serine protease catalytic triad (His, Asp, and Ser). The enzymatic activity is enhanced by interacting with the central 40 amino acid of NS2B which acts as an essential cofactor. The NS3 protease domain has an overall structure of two barrels made of six beta sheets each, with the active site located in the cleft between the barrels. The NS2B hydrophilic core cofactor contributes one of the N-terminal beta sheets [ PUBMED:17400917 , PUBMED:19693793 , PUBMED:20042502 ].

Gene Ontology

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Domain organisation

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This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

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Curation and family details

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Seed source: Pfam-B_199 (release 3.0)
Previous IDs: Flavi_helicase;
Type: Family
Sequence Ontology: SO:0100021
Author: Finn RD
Number in seed: 7
Number in full: 37
Average length of the domain: 86.90 aa
Average identity of full alignment: 21 %
Average coverage of the sequence by the domain: 14.32 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.0 20.0
Trusted cut-off 20.0 20.0
Noise cut-off 19.9 19.9
Model length: 131
Family (HMM) version: 24
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Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Peptidase_S7 domain has been found. There are 119 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
P33276 View 3D Structure Click here
P75194 View 3D Structure Click here
P75196 View 3D Structure Click here
P75200 View 3D Structure Click here
P75203 View 3D Structure Click here
Q50336 View 3D Structure Click here
Q50338 View 3D Structure Click here