P35628 (ITR4_LUFCY) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Trypsin inhibitor 4 Alternative name(s): TGTI-I Trypsin inhibitor I
Organism	Luffa cylindrica (Smooth loofah) (Sponge gourd)
Taxonomic identifier	3670 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Viridiplantae › Streptophyta › Streptophytina › Embryophyta › Tracheophyta › Euphyllophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › fabids › Cucurbitales › Cucurbitaceae › Sicyoeae › Luffa

Protein attributes

Sequence length	28 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Inhibits trypsin.
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)
Biological_process	negative regulation of endopeptidase activity Inferred from electronic annotation. Source: GOC
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 – 28	28	Trypsin inhibitor 4		PRO_0000044385
Sites
	Site	4 – 5	2	Reactive bond
Amino acid modifications
	Disulfide bond	2 ↔ 19		By similarity
	Disulfide bond	9 ↔ 21		By similarity
	Disulfide bond	15 ↔ 27		By similarity

Sequences

	Sequence		Length	Mass (Da)
	P35628 [UniParc]. Last modified June 1, 1994. Version 1. Checksum: D5E0FC428239021F	FASTA	28	2,994
	10 20 ICPRILMPCS SDSDCLAECI CLENGFCG

References

[1]	"Protein, cDNA, and genomic DNA sequences of the towel gourd trypsin inhibitor. A squash family inhibitor." Ling M.-H., Qi H.-Y., Chi C.-W. J. Biol. Chem. 268:810-814(1993) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE.

Cross-references

Sequence databases
PIR	B45041.
3D structure databases
ProteinModelPortal	P35628.
SMR	P35628. Positions 1-28.
ModBase	Search...
Protein family/group databases
MEROPS	I07.010.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
InterPro	IPR000737. Prot_inh_squash. IPR011052. Proteinase_amylase_inhib_dom. [Graphical view]
Pfam	PF00299. Squash. 1 hit. [Graphical view]
PRINTS	PR00293. SQUASHINHBTR.
SMART	SM00286. PTI. 1 hit. [Graphical view]
SUPFAM	SSF57027. Prot_amyl_inhib. 1 hit.
PROSITE	PS00286. SQUASH_INHIBITOR. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

ITR4_LUFCY

Accession

Primary (citable) accession number: P35628

Entry history

Integrated into UniProtKB/Swiss-Prot:	June 1, 1994
Last sequence update:	June 1, 1994
Last modified:	April 3, 2013
This is version 57 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Plant Protein Annotation Program