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Protein

Kunitz-type serine protease inhibitor LmKTT-1a

Gene
N/A
Organism
Lychas mucronatus (Chinese swimming scorpion)
Status
Reviewed-Annotation score: Annotation score: 4 out of 5-Experimental evidence at protein leveli

Functioni

Dual-function toxin that completely inhibits trypsin activity at a molar ratio of 1:1 (Ki=140 nM) and that inhibits mKv1.3/KCNA3 potassium channel currents (1 µM inhibits 50% of currents) (IC50=1.58 µM). Shows also weak inhibition on Kv1.1/KCNA1 (1 µM inhibits 25% of currents) and Kv1.2/KCNA2 (1 µM inhibits 25% of currents).2 Publications

Miscellaneous

Has no effect on chymotrypsin and elastase.1 Publication

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei35Key residue that directly interacts with the S1 pocket of trypsinBy similarity1

GO - Molecular functioni

  • serine-type endopeptidase inhibitor activity Source: UniProtKB

GO - Biological processi

Keywordsi

Molecular functionIon channel impairing toxin, Potassium channel impairing toxin, Protease inhibitor, Serine protease inhibitor, Toxin, Voltage-gated potassium channel impairing toxin

Names & Taxonomyi

Protein namesi
Recommended name:
Kunitz-type serine protease inhibitor LmKTT-1a
Alternative name(s):
Delta-KTx 2.1
SdPII
OrganismiLychas mucronatus (Chinese swimming scorpion)
Taxonomic identifieri172552 [NCBI]
Taxonomic lineageiEukaryotaMetazoaEcdysozoaArthropodaChelicerataArachnidaScorpionesButhidaButhoideaButhidaeLychas

Subcellular locationi

GO - Cellular componenti

  • extracellular region Source: UniProtKB
  • host cell membrane Source: UniProtKB

Keywords - Cellular componenti

Secreted

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi72C → A: 5-fold decrease in trypsin inhibition, and no change in Kv1.3/KCNA3 inhibition; when associated with A-80. 1 Publication1
Mutagenesisi80C → A: 5-fold decrease in trypsin inhibition, and no change in Kv1.3/KCNA3 inhibition; when associated with A-72. 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Signal peptidei1 – 21Sequence analysisAdd BLAST21
ChainiPRO_000041810222 – 80Kunitz-type serine protease inhibitor LmKTT-1aAdd BLAST59

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Disulfide bondi25 ↔ 75PROSITE-ProRule annotation1 Publication
Disulfide bondi50 ↔ 71PROSITE-ProRule annotation1 Publication
Disulfide bondi72 ↔ 80PROSITE-ProRule annotation1 Publication

Post-translational modificationi

Lacks the conserved CysII-CysIV disulfide bond but contains 2 cysteine residues at the C-terminus that generate a new disulfide bond.

Keywords - PTMi

Disulfide bond

Expressioni

Tissue specificityi

Expressed by the venom gland.

Structurei

Secondary structure

180
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi38 – 44Combined sources7
Turni45 – 48Combined sources4
Beta strandi49 – 55Combined sources7
Helixi70 – 76Combined sources7

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
2M01NMR-A22-80[»]
SMRiP0DJ46.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini25 – 75BPTI/Kunitz inhibitorPROSITE-ProRule annotationAdd BLAST51

Sequence similaritiesi

Keywords - Domaini

Signal

Family and domain databases

Gene3Di4.10.410.10. 1 hit.
InterProiView protein in InterPro
IPR002223. Kunitz_BPTI.
PfamiView protein in Pfam
PF00014. Kunitz_BPTI. 1 hit.
PRINTSiPR00759. BASICPTASE.
SMARTiView protein in SMART
SM00131. KU. 1 hit.
SUPFAMiSSF57362. SSF57362. 1 hit.
PROSITEiView protein in PROSITE
PS50279. BPTI_KUNITZ_2. 1 hit.

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P0DJ46-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MKSFLLIALV LFFLFVSYAS AKKKCQLPSD VGKGKASFTR YYYNEESGKC
60 70 80
ETFIYGGVGG NSNNFLTKED CCRECAQGSC
Length:80
Mass (Da):8,864
Last modified:July 11, 2012 - v1
Checksum:iD83664064E8A8CBC
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
GT028614 mRNA. No translation available.

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.

Entry informationi

Entry nameiVKT21_LYCMC
AccessioniPrimary (citable) accession number: P0DJ46
Secondary accession number(s): P0CJ20
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 11, 2012
Last sequence update: July 11, 2012
Last modified: February 15, 2017
This is version 18 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  2. Scorpion potassium channel toxins
    Nomenclature of scorpion potassium channel toxins and list of entries
  3. SIMILARITY comments
    Index of protein domains and families