Reviewed, UniProtKB/Swiss-Prot P83394 (ITR3_CYCPE)

Names and origin

Protein names	Recommended name:     Trypsin inhibitor 3 Alternative name(s):     Trypsin inhibitor III     CyPTI-III Cleaved into the following chain:     1- Recommended name:             Trypsin inhibitor 1         Alternative name(s):             Trypsin inhibitor I             CyPTI-I
Organism	Cyclanthera pedata (Achocha) (Caihua)
Taxonomic identifier	198836 [NCBI]
Taxonomic lineage	Eukaryota › Viridiplantae › Streptophyta › Embryophyta › Tracheophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › eurosids I › Cucurbitales › Cucurbitaceae › Cyclanthera

Protein attributes

Sequence length	29 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Strongly inhibits trypsin, weakly inhibits chymotrypsin.
Subcellular location	Secreted.
Domain	The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin By similarity.
Sequence similarities	Belongs to the protease inhibitor I7 (squash-type serine protease inhibitor) family. [View classification]

Ontologies

Keywords
Cellular component	Secreted
Domain	Knottin
Molecular function	Protease inhibitor Serine protease inhibitor
PTM	Disulfide bond
Technical term	Direct protein sequencing
Gene Ontology (GO)
Cellular component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	serine-type endopeptidase inhibitor activity Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Peptide	1 – 29	29	Trypsin inhibitor 3		PRO_0000033204
	Peptide	2 – 29	28	Trypsin inhibitor 1		PRO_0000033205
Sites
	Site	5 – 6	2	Reactive bond
Amino acid modifications
	Disulfide bond	3 ↔ 20		By similarity UniProtKB P01074
	Disulfide bond	10 ↔ 22		By similarity UniProtKB P01074
	Disulfide bond	16 ↔ 28		By similarity UniProtKB P01074

Sequences

	Sequence		Length	Mass (Da)
	P83394-1 [UniParc]. Last modified October 1, 2002. Version 1. Checksum: D5FEFF8A5FEDCC2F	FASTA	29	3,195
	10 20 RICPRILMEC KADSDCLAQC ICEESGFCG

References

[1]	"Non-conventional affinity chromatography of serine proteinases and their inhibitors." Polanowski A., Wilimowska-Pelc A., Kowalska J., Grybel J., Zelazko M., Wilusz T. Acta Biochim. Pol. 50:765-773(2003) [PubMed: 14515156] [Abstract] Cited for: PROTEIN SEQUENCE, REACTIVE SITE. Tissue: Seed.
[2]	"Isolation and primary structures of seven serine proteinase inhibitors from Cyclanthera pedata seeds." Kowalska J., Zablocka A., Wilusz T. Biochim. Biophys. Acta 1760:1054-1063(2006) [PubMed: 16635550] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION, REACTIVE SITE. Tissue: Seed.

Cross-references

3D structure databases
HSSP	HSSP built from PDB template 1CTI based on UniProtKB P01074.
ModBase	Search...
Family and domain databases
InterPro	IPR000737. Prot_inh_squash. [Graphical view]
Pfam	PF00299. Squash. 1 hit. [Graphical view]
PRINTS	PR00293. SQUASHINHBTR.
ProDom	PD003401. Prot_inh_squash. 1 hit. [Graphical view] [Entries sharing at least one domain]
SMART	SM00286. PTI. 1 hit. [Graphical view]
PROSITE	PS00286. SQUASH_INHIBITOR. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

ITR3_CYCPE

Accession

Primary (citable) accession number: P83394
Secondary accession number(s): P83392

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 2002
Last sequence update:	October 1, 2002
Last modified:	June 16, 2009
This is version 46 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

PPAP (Plant Proteome Annotation Project)