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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: 5 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

  • serine-type endopeptidase inhibitor activity Source: CAFA

GO - Biological processi

  • negative regulation of serine-type endopeptidase activity Source: CAFA

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

Extracellular region or secreted Cytosol Plasma membrane Cell wall Cytoskeleton Vacuole Chloroplast Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertion Graphics by Christian Stolte; Source: COMPARTMENTS

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

P82409: Molecular mass is 3453±0.2 Da from positions 1 - 34. Determined by ESI. 1 Publication

Similar proteinsi

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: May 10, 2017
This is version 95 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