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Protein

Delta-actitoxin-Axm1b

Gene
N/A
Organism
Anthopleura xanthogrammica (Giant green sea anemone)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Binds specifically to voltage-gated sodium channels (Nav) (site 3), thereby delaying their inactivation. This toxin has the highest affinity of all anemone toxins for the mammalian sodium channel, whereas its paralog Anthopleurin-A retains the greatest capacity to discriminate between cardiac (Nav1.5/SCN5A) and neuronal sodium channels (PubMed:8916901). When tested electrophysiologically, this toxin exhibits a high affinity for multiple sodium channels with a 50-fold preference for rat cardiac (Nav1.5/SCN5A) over neuronal channels (0.1 nM versus 5 nM). When tested by ion flux, the affinities are similar and appear to have higher affinity (9 nM versus 22 nM) (PubMed:8276803, PubMed:7612595). The residue Lys-37 of this toxin has been shown to interact with channel Nav1.5 (residue Asp-1612 in rat and Asp-1610 in human), which is located in the DIV S3-S4 linker (corresponding to channel site 3) (PubMed:9417050, PubMed:24898004). Selectively modifies sodium channel inactivation from the open state with little effect on channel activation or on inactivation from closed states (By similarity). Does not display phospholipid-binding activities, suggesting that the domain IV S3-S4 linker is located at the extracellular surface and not buried in the phospholipid bilayer (PubMed:15632158).By similarity7 Publications

Sites

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sitei7 – 71Structurally important1 Publication
Sitei9 – 91Important for sodium channel affinity and for toxin structure1 Publication
Sitei10 – 101Important for affinity to sodium channel, probably due to the flexibility this residue gives to the Arg-14 loop1 Publication
Sitei12 – 121Key residue for binding both cardiac and neuronal sodium channels1 Publication
Sitei13 – 131Important for sodium channel affinity1 Publication
Sitei14 – 141Not essential for sodium channel affinity1 Publication
Sitei15 – 151Important for affinity to sodium channel, probably due to the flexibility this residue gives to the Arg-14 loop1 Publication
Sitei16 – 161Binds to sodium channel1 Publication
Sitei17 – 171Has its side chain oriented away from the channel in the binary complex1 Publication
Sitei18 – 181Important for high affinity to sodium channel1 Publication
Sitei19 – 191Binds to sodium channel1 Publication
Sitei20 – 201Structurally important1 Publication
Sitei33 – 331Important for channel affinity1 Publication
Sitei34 – 341Not important for channel affinity and toxin structure1 Publication
Sitei37 – 371Important for channel affinity (interacts with rat Nav1.5 channel residue Asp-1612)2 Publications
Sitei39 – 391Not important for channel affinity and toxin structure1 Publication
Sitei43 – 431Structurally important1 Publication
Sitei45 – 451Does not affect binding, but may affect the stabilization of the cardiac channel open conformation1 Publication
Sitei48 – 481Binds to sodium channel1 Publication
Sitei49 – 491Important for most of the cardiac specificity1 Publication

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Cardiotoxin, Ion channel impairing toxin, Neurotoxin, Toxin, Voltage-gated sodium channel impairing toxin

Names & Taxonomyi

Protein namesi
Recommended name:
Delta-actitoxin-Axm1b1 Publication
Short name:
Delta-AITX-Axm1b1 Publication
Alternative name(s):
Anthopleurin-B1 Publication
Short name:
AP-B1 Publication
Short name:
ApB1 Publication
OrganismiAnthopleura xanthogrammica (Giant green sea anemone)
Taxonomic identifieri6112 [NCBI]
Taxonomic lineageiEukaryotaMetazoaCnidariaAnthozoaHexacoralliaActiniariaNynantheaeActiniidaeAnthopleura

Subcellular locationi

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Nematocyst, Secreted

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Mutagenesisi3 – 31P → S: Minor decrease in affinity for sodium channels (4.7-fold on neuronal and 2-fold on cardiac (Nav1.5) channels). 1 Publication
Mutagenesisi7 – 71D → A or N: Incorrect folding or very limited amount of mutant obtained. 1 Publication
Mutagenesisi7 – 71D → K: Incorrect folding; when associated with D-37. 1 Publication
Mutagenesisi7 – 71D → N: Small decrease in affinity (4-6-fold), and very limited amount of mutant obtained. 1 Publication
Mutagenesisi9 – 91D → A: Major decrease in affinity for both cardiac (Nav1.5) (300-fold) and neuronal (100-fold) channels. 1 Publication
Mutagenesisi9 – 91D → N: Decrease in affinity for both cardiac (Nav1.5) (10-fold) and neuronal (8-fold) channels. 1 Publication
Mutagenesisi10 – 101G → A: Decrease in affinity for both cardiac (Nav1.5) (15-fold) and neuronal (450-fold) channels, as well as a 30-fold increase in discrimination for Nav1.5. Decrease in affinity for cardiac (Nav1.5) (600-fold); when associated with A-15. Not correctly folded; when associated with A-20. 1 Publication
Mutagenesisi12 – 121R → A: Major decrease in affinity for both cardiac (Nav1.5) and neuronal sodium channels. 1 Publication
Mutagenesisi12 – 121R → K: Minor effect on toxicity. 1 Publication
Mutagenesisi12 – 121R → S: Minor effect on toxicity. Decrease in affinity for both cardiac (Nav1.5) (5-fold) and neuronal (37-fold) channels; when associated with Q-49 (tested by ion flux studies). Loss of discrimination between cardiac and neuronal channels; when associated with Val-13 and Q-49. 3 Publications
Mutagenesisi13 – 131P → V: Decrease in affinity for both cardiac (Nav1.5) (9-fold) and neuronal channels (9-fold). Loss of discrimination between cardiac and neuronal channels; when associated with S-12 and Q-49. 1 Publication
Mutagenesisi14 – 141R → A: Minor effect on toxicity. 1 Publication
Mutagenesisi14 – 141R → K: Minor effect on toxicity. 1 Publication
Mutagenesisi14 – 141R → Q: Minor effect on toxicity. Decrease in affinity for both cardiac (Nav1.5) (56-fold) and neuronal (72-fold) channels; when associated with S-12 (tested by ion flux studies). Decrease in affinity for both cardiac (Nav1.5) (13-fold) and neuronal (27-fold) channels; when associated with A-48 (tested by ion flux studies). 2 Publications
Mutagenesisi15 – 151G → A: Decrease in affinity for both cardiac (Nav1.5) (13-fold) and neuronal (600-fold) channels, as well as a 50-fold increase in discrimination for Nav1.5. Decrease in affinity for cardiac (Nav1.5) (600-fold); when associated with A-10. 1 Publication
Mutagenesisi16 – 161N → A: Decrease in affinity for cardiac (Nav1.5) (8-fold) channels. 1 Publication
Mutagenesisi16 – 161N → D: Decrease in affinity for both cardiac (Nav1.5) (500-fold) and neuronal (3600-fold) channels. 1 Publication
Mutagenesisi16 – 161N → R: Decrease in affinity for both cardiac (Nav1.5) (5-fold) and neuronal (56-fold) channels. 1 Publication
Mutagenesisi17 – 171T → A or D: No change in activity. 1 Publication
Mutagenesisi18 – 181L → A: Major decrease in affinity for both cardiac (Nav1.5) (330-fold) and neuronal (34-fold) channels, as well as a 9.5-fold decrease in discrimination for Nav1.5. 1 Publication
Mutagenesisi18 – 181L → V: Decrease in affinity for both cardiac (Nav1.5) and neuronal channels. 1 Publication
Mutagenesisi19 – 191S → A: Decrease in affinity for cardiac (Nav1.5) (5.6-fold) channels. 1 Publication
Mutagenesisi19 – 191S → D: Major decrease in affinity for both cardiac (Nav1.5) (85-fold) and neuronal (653-fold) channels. 1 Publication
Mutagenesisi19 – 191S → R: Decrease in affinity for both cardiac (Nav1.5) (5.7-fold) and neuronal (27-fold) channels. 1 Publication
Mutagenesisi20 – 201G → A: Incorrect folding. Incorrect folding; when associated with A-10. 1 Publication
Mutagenesisi21 – 211I → T: Minor decrease in affinity for sodium channels (2.2-fold on neuronal and 2.9-fold on cardiac (Nav1.5) channels). 1 Publication
Mutagenesisi24 – 241F → L: Minor decrease in affinity for sodium channels (4.8-fold on neuronal and 2.4-fold on cardiac (Nav1.5) channels). 1 Publication
Mutagenesisi33 – 331W → A: No mutant obtained. 1 Publication
Mutagenesisi33 – 331W → F: Major decrease in affinity for both cardiac (Nav1.5) (31-fold) and neuronal (50-fold) channels (tested by ion flux studies). This mutant is the first ApB mutant that displays a significantly altered association rate (K(on)). 1 Publication
Mutagenesisi33 – 331W → S: No mutant obtained. 1 Publication
Mutagenesisi33 – 331W → Y: Minor decrease in affinity for both cardiac (Nav1.5) (5.6-fold) and neuronal (5-fold) channels. 1 Publication
Mutagenesisi34 – 341H → A: Minor decrease in affinity. 1 Publication
Mutagenesisi37 – 371K → A: Decrease in affinity for both cardiac (Nav1.5) (11-fold) and neuronal (7-fold) channels. 1 Publication
Mutagenesisi37 – 371K → A: Decrease in affinity for cardiac (Nav1.5) channels (13-fold) (with decrease in K(on) and increase in K(off)). 1 Publication
Mutagenesisi37 – 371K → D: Incorrect folding; when associated with K-7. 1 Publication
Mutagenesisi39 – 391H → A: No change in activity. 1 Publication
Mutagenesisi39 – 391H → A: Small decrease in affinity for cardiac (Nav1.5) channels (1.1-fold) (with increase in both K(on) and K(off)). 1 Publication
Mutagenesisi42 – 421N → T: Minor decrease in affinity for sodium channels (1.1-fold on neuronal and 3.4-fold on cardiac (Nav1.5) channels). 1 Publication
Mutagenesisi43 – 431I → A, G or F: Incorrect folding. 1 Publication
Mutagenesisi43 – 431I → L or V: Small decrease in apparent binding affinity for both neuronal and cardiac (Nav1.5) channels (tested by ion flux studies). 1 Publication
Mutagenesisi45 – 451W → A: Minor decrease in affinity for both cardiac (Nav1.5) (7.7-fold) and neuronal (4-fold) channels (tested by ion flux studies). 1 Publication
Mutagenesisi45 – 451W → F: Minor decrease in affinity for both cardiac (Nav1.5) (2-4-fold) (with decrease in K(on) and increase in K(off)) and neuronal (5-fold) channels (tested by ion flux studies). 2 Publications
Mutagenesisi45 – 451W → S: Minor decrease in affinity for both cardiac (Nav1.5) (3.3-fold) and neuronal (7-fold) channels (tested by ion flux studies). 1 Publication
Mutagenesisi48 – 481K → A: Minor effect on toxicity. Decrease in affinity for both cardiac (Nav1.5) (13-fold) and neuronal (27-fold) channels; when associated with Q-14 (tested by ion flux studies). 2 Publications
Mutagenesisi48 – 481K → Q: Minor effect on toxicity. 1 Publication
Mutagenesisi48 – 481K → R: Minor effect on toxicity. 1 Publication
Mutagenesisi49 – 491K → A: Minor effect on toxicity. 1 Publication
Mutagenesisi49 – 491K → Q: Minor effect on toxicity. Decrease in affinity for both cardiac (Nav1.5) (5-fold) and neuronal (37-fold) channels; when associated with S-12 (tested by ion flux studies). Loss of discrimination between cardiac and neuronal channels; when associated with S-12 and V-13. 3 Publications
Mutagenesisi49 – 491K → R: Minor effect on toxicity. 1 Publication

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 4949Delta-actitoxin-Axm1b1 PublicationPRO_0000221516Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Disulfide bondi4 ↔ 461 Publication
Disulfide bondi6 ↔ 361 Publication
Disulfide bondi29 ↔ 471 Publication

Keywords - PTMi

Disulfide bond

Structurei

Secondary structure

1
49
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Turni14 – 174Combined sources
Beta strandi20 – 234Combined sources
Beta strandi42 – 476Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1APFNMR-A1-49[»]
ProteinModelPortaliP01531.
SMRiP01531. Positions 1-49.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP01531.

Family & Domainsi

Region

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Regioni1 – 77Well-structured region2 Publications
Regioni8 – 1710Arg-14 loop (non-well-structured region)2 Publications
Regioni18 – 4932Well-structured region2 PublicationsAdd
BLAST

Sequence similaritiesi

Family and domain databases

Gene3Di2.20.20.10. 1 hit.
InterProiIPR000693. Anenome_toxin.
IPR023355. Myo_neuro_toxin.
[Graphical view]
PfamiPF00706. Toxin_4. 1 hit.
[Graphical view]
PIRSFiPIRSF001905. Anenome_toxin. 1 hit.

Sequencei

Sequence statusi: Complete.

P01531-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40 
GVPCLCDSDG PRPRGNTLSG ILWFYPSGCP SGWHNCKAHG PNIGWCCKK
Length:49
Mass (Da):5,274
Last modified:January 1, 1988 - v1
Checksum:i7BD237179065AE90
GO

Sequence cautioni

The sequence AAA27737 differs from that shown. Reason: Erroneous initiation. Translation N-terminally shortened.Curated

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti12 – 132RP → PN AA sequence (PubMed:6108877).Curated
Sequence conflicti25 – 251Y → A AA sequence (PubMed:6108877).Curated

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M90675 mRNA. Translation: AAA27737.1. Different initiation.
PIRiA92547. NAXAB.

Cross-referencesi

Web resourcesi

Wikipedia

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M90675 mRNA. Translation: AAA27737.1. Different initiation.
PIRiA92547. NAXAB.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1APFNMR-A1-49[»]
ProteinModelPortaliP01531.
SMRiP01531. Positions 1-49.
ModBaseiSearch...
MobiDBiSearch...

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Miscellaneous databases

EvolutionaryTraceiP01531.

Family and domain databases

Gene3Di2.20.20.10. 1 hit.
InterProiIPR000693. Anenome_toxin.
IPR023355. Myo_neuro_toxin.
[Graphical view]
PfamiPF00706. Toxin_4. 1 hit.
[Graphical view]
PIRSFiPIRSF001905. Anenome_toxin. 1 hit.
ProtoNetiSearch...

Entry informationi

Entry nameiNA1B_ANTXA
AccessioniPrimary (citable) accession number: P01531
Secondary accession number(s): V9GZA1
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: January 1, 1988
Last modified: October 14, 2015
This is version 92 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program

Miscellaneousi

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

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.