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Protein

Trypsin inhibitor 2

Gene
N/A
Organism
Momordica cochinchinensis (Spiny bitter cucumber) (Muricia cochinchinensis)
Status
Reviewed-Annotation score: Annotation score: 4 out of 5-Experimental evidence at protein leveli

Functioni

Inhibits trypsin; probably participates in a plant defense mechanism.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei10 – 11Reactive bond2

GO - Molecular functioni

Keywordsi

Molecular functionProtease inhibitor, Serine protease inhibitor

Protein family/group databases

MEROPSiI07.004.

Names & Taxonomyi

Protein namesi
Recommended name:
Trypsin inhibitor 2
Alternative name(s):
MCoTI-II
Trypsin inhibitor II
OrganismiMomordica cochinchinensis (Spiny bitter cucumber) (Muricia cochinchinensis)
Taxonomic identifieri3674 [NCBI]
Taxonomic lineageiEukaryotaViridiplantaeStreptophytaEmbryophytaTracheophytaSpermatophytaMagnoliophytaeudicotyledonsGunneridaePentapetalaerosidsfabidsCucurbitalesCucurbitaceaeMomordiceaeMomordica

Subcellular locationi

GO - Cellular componenti

Keywords - Cellular componenti

Secreted

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
PeptideiPRO_00000448581 – 34Trypsin inhibitor 2Add BLAST34

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Cross-linki1 ↔ 34Cyclopeptide (Ser-Gly)
Cross-linki4 ↔ 5(2-aminosuccinimidyl)acetic acid (Asp-Gly); alternate
Cross-linki4 ↔ 5Isoaspartyl glycine isopeptide (Asp-Gly); alternate
Disulfide bondi8 ↔ 25By similarity
Disulfide bondi15 ↔ 27By similarity
Disulfide bondi21 ↔ 33By similarity

Post-translational modificationi

A cyclic succinimide probably forms by loss of water between Asp-4 and Gly-5, that can then rehydrate to either the original peptide bond or to a beta-aspartyl isopeptide bond. Three isoforms of MCoTI-II are detected, two with the parent molecular weight, corresponding to the unmodified and proposed isopeptide forms, and one with a molecular weight 18 Da lower, corresponding to a succinimide cross-linked form.
This is a cyclic peptide.

Keywords - PTMi

Disulfide bond, Isopeptide bond

Structurei

Secondary structure

134
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Helixi18 – 20Combined sources3
Beta strandi25 – 27Combined sources3
Beta strandi31 – 34Combined sources4

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1HA9NMR-A1-34[»]
1IB9NMR-A1-34[»]
2C4BX-ray1.30A/B6-21[»]
2IT8NMR-A6-34[»]
2MT8NMR-A14-34[»]
2PO8NMR-A8-34[»]
4GUXX-ray1.80D/E/F1-34[»]
DisProtiDP00680.
ProteinModelPortaliP82409.
SMRiP82409.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP82409.

Family & Domainsi

Domaini

The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin.By similarity

Sequence similaritiesi

Keywords - Domaini

Knottin

Family and domain databases

CDDicd00150. PlantTI. 1 hit.
InterProiView protein in InterPro
IPR000737. Prot_inh_squash.
IPR011052. Proteinase_amylase_inhib_dom.
PfamiView protein in Pfam
PF00299. Squash. 1 hit.
SUPFAMiSSF57027. SSF57027. 1 hit.
PROSITEiView protein in PROSITE
PS00286. SQUASH_INHIBITOR. 1 hit.

Sequencei

Sequence statusi: Complete.

P82409-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30 
SGSDGGVCPK ILKKCRRDSD CPGACICRGN GYCG
Length:34
Mass (Da):3,477
Last modified:June 1, 2000 - v1
Checksum:i8F7D0B4C048BB93A
GO

Mass spectrometryi

Molecular mass is 3453±0.2 Da from positions 1 - 34. Determined by ESI. 1 Publication

Cross-referencesi

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1HA9NMR-A1-34[»]
1IB9NMR-A1-34[»]
2C4BX-ray1.30A/B6-21[»]
2IT8NMR-A6-34[»]
2MT8NMR-A14-34[»]
2PO8NMR-A8-34[»]
4GUXX-ray1.80D/E/F1-34[»]
DisProtiDP00680.
ProteinModelPortaliP82409.
SMRiP82409.
ModBaseiSearch...
MobiDBiSearch...

Protein family/group databases

MEROPSiI07.004.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Miscellaneous databases

EvolutionaryTraceiP82409.

Family and domain databases

CDDicd00150. PlantTI. 1 hit.
InterProiView protein in InterPro
IPR000737. Prot_inh_squash.
IPR011052. Proteinase_amylase_inhib_dom.
PfamiView protein in Pfam
PF00299. Squash. 1 hit.
SUPFAMiSSF57027. SSF57027. 1 hit.
PROSITEiView protein in PROSITE
PS00286. SQUASH_INHIBITOR. 1 hit.
ProtoNetiSearch...

Entry informationi

Entry nameiITR2_MOMCO
AccessioniPrimary (citable) accession number: P82409
Entry historyiIntegrated into UniProtKB/Swiss-Prot: December 1, 2000
Last sequence update: June 1, 2000
Last modified: November 2, 2016
This is version 93 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program

Miscellaneousi

Caution

The genomic sequence for this protein is not available, so Asp-4 may possibly be an asparagine which is known to be more labile when immediately followed by a glycine.Curated

Keywords - Technical termi

3D-structure, Direct protein sequencing

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  2. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.