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P49268 (TXP3_APOSC) Reviewed, UniProtKB/Swiss-Prot

Last modified July 9, 2014. Version 61. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (2) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Web links·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
Mu-cyrtautoxin-As1a

Short name=Mu-CUTX-As1a
Alternative name(s):
Aptotoxin III
Short name=Aps III
Aptotoxin-3
Short name=Aps-3
Paralytic peptide III
Short name=PP III
U2-cyrtautoxin-As1a
Short name=U2-CUTX-As1a
OrganismApomastus schlingeri (Trap-door spider) (Aptostichus schlingeri)
Taxonomic identifier12944 [NCBI]
Taxonomic lineageEukaryotaMetazoaEcdysozoaArthropodaChelicerataArachnidaAraneaeMygalomorphaeEuctenizidaeApomastus

Protein attributes

Sequence length37 AA.
Sequence statusComplete.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

The recombinant mu-cyrtautoxin-As1a potently and voltage-independently blocks voltage-gated sodium channels (Nav) of insects. It acts by pluging the outer vestibule of the channel. It acts in combination with a weak (30%) voltage-independent block of insect voltage-gated calcium (Cav) channels (low-voltage and high-voltage channels). Tested on DUM neurons, it inhibits sodium currents with an IC50 of 540 nM (and a Hill coefficient >1, reflecting an incomplete block at higher concentrations). It induces flaccid paralysis in adult Australian sheep blowfly Lucilia cuprina (Ref.2). Is both paralytic and lethal, when injected into lepidopteran larvae. Is a slower acting toxin, being lethal at 24 hours, but not paralytic at 1 hour post-injection (Ref.1). Ref.2

Subcellular location

Secreted.

Tissue specificity

Expressed by the venom gland.

Domain

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

Toxic dose

LD50 is 133 pmol/g against the tobacco hornworm Manduca sexta (Ref.1) and more than 2.66 pmol/g against the beet armyworm Spodoptera exigua (Ref.1). Ref.1

PD50 measured 24h after injection in adult Australian sheep blowfly Lucilia cuprina is 700 +- 35 pmol/g (Ref.2). Ref.1

Miscellaneous

Does not modulate the activity of delayed-rectifier, "A-type" or BKCa potassium channels (Ref.2).

Sequence similarities

Belongs to the insecticidal toxin ABC family.

Caution

No comparison between the natural toxin and the recombinant one has been done (Ref.2) to attest that the results can be also attributed to the natural toxin (mode of action and disulfide bonds).

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Peptide1 – 3737Mu-cyrtautoxin-As1a
PRO_0000044986

Amino acid modifications

Disulfide bond1 ↔ 15 Ref.2
Disulfide bond8 ↔ 19 Ref.2
Disulfide bond14 ↔ 35 Ref.2
Disulfide bond26 ↔ 31 Ref.2

Secondary structure

.......... 37
Helix Strand Turn

Details...

Sequences

Sequence LengthMass (Da)Tools
P49268 [UniParc].

Last modified February 1, 1996. Version 1.
Checksum: CBD01091694E1908

FASTA373,769
        10         20         30 
CNSKGTPCTN ADECCGGKCA YNVWNCIGGG CSKTCGY 

« Hide

References

[1]"Identification of insecticidal peptides from venom of the trap-door spider, Aptostichus schlingeri (Ctenizidae)."
Skinner W.S., Dennis P.A., Li J.P., Quistad G.B.
Toxicon 30:1043-1050(1992) [PubMed] [Europe PMC] [Abstract]
Cited for: PROTEIN SEQUENCE, BIOASSAY, LETHAL DOSE.
Tissue: Venom.
[2]"The insecticidal neurotoxin Aps III is an atypical knottin peptide that potently blocks insect voltage-gated sodium channels."
Bende N.S., Kang E., Herzig V., Bosmans F., Nicholson G.M., Mobli M., King G.F.
Biochem. Pharmacol. 85:1542-1554(2013) [PubMed] [Europe PMC] [Abstract]
Cited for: FUNCTION, STRUCTURE BY NMR, DISULFIDE BONDS.

Cross-references

Sequence databases

PIRE44007.

3D structure databases

PDBe
RCSB-PDB
PDBj
EntryMethodResolution (Å)ChainPositionsPDBsum
2M36NMR-A1-37[»]
ModBaseSearch...
MobiDBSearch...

Protein family/group databases

TCDB8.B.21.1.1. the spider insecticidal neurotoxin cyrtautoxin (cyrautoxin) family.

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Organism-specific databases

ArachnoServerAS000403. mu-cyrtautoxin-As1a.

Family and domain databases

InterProIPR012626. Spider_insecticidal_peptide.
[Graphical view]
PfamPF08091. Toxin_21. 1 hit.
[Graphical view]
ProtoNetSearch...

Entry information

Entry nameTXP3_APOSC
AccessionPrimary (citable) accession number: P49268
Entry history
Integrated into UniProtKB/Swiss-Prot: February 1, 1996
Last sequence update: February 1, 1996
Last modified: July 9, 2014
This is version 61 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families

PDB cross-references

Index of Protein Data Bank (PDB) cross-references