P01531 (TXAB_ANTXA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Anthopleurin-B Short name=AP-B Short name=ApB
Organism	Anthopleura xanthogrammica (Giant green sea anemone)
Taxonomic identifier	6112 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Cnidaria › Anthozoa › Hexacorallia › Actiniaria › Nynantheae › Actiniidae › Anthopleura

Protein attributes

Sequence length	49 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Binds specifically to the sodium channel (site 3) (Nav), thereby delaying its inactivation during signal transduction. Thus it strongly stimulates mammalian cardiac muscle contraction. Does not display phospholipid-binding activity. Anthopleurin-B is the most potent peptide heart stimulator isolated from the sea anemone.
Subcellular location	Secreted. Nematocyst.
Sequence similarities	Belongs to the sea anemone sodium channel inhibitory toxin family. Type I subfamily.

Ontologies

Keywords
Cellular component	Nematocyst Secreted
Molecular function	Ion channel impairing toxin Neurotoxin Sodium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological_process	regulation of signal transduction Inferred from electronic annotation. Source: InterPro
Cellular_component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell nematocyst Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular_function	sodium channel 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

Chain

1 – 49

49

Anthopleurin-B

PRO_0000221516

Sites

Site

16

1

Binds to sodium channel

Site

18

1

Binds to sodium channel

Site

19

1

Binds to sodium channel

Site

33

1

Binds to sodium channel

Site

37

1

Binds to sodium channel

Amino acid modifications

Disulfide bond

4 ↔ 46

Ref.8

Disulfide bond

6 ↔ 36

Ref.8

Disulfide bond

29 ↔ 47

Ref.8

Experimental info

Sequence conflict

12 – 13

2

RP → PN AA sequence Ref.2

Sequence conflict

25

1

Y → A AA sequence Ref.2

Secondary structure

1

.

.

.

.

.

.

.

49

Helix Strand Turn

Details...

Turn

14 – 17

4

Beta strand

20 – 23

4

Beta strand

42 – 47

6

Sequences

	Sequence		Length	Mass (Da)
	P01531 [UniParc]. Last modified January 1, 1988. Version 1. Checksum: 7BD237179065AE90	FASTA	49	5,274
	10 20 30 40 GVPCLCDSDG PRPRGNTLSG ILWFYPSGCP SGWHNCKAHG PNIGWCCKK

References

[1]	"Amino acid sequence of the Anthopleura xanthogrammica heart stimulant, anthopleurin-B." Reimer N.S., Yasunobu C.L., Yasunobu K.T., Norton T.R. J. Biol. Chem. 260:8690-8693(1985) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Nematoblast.
[2]	"Cardiotonic polypeptides from Anthopleura xanthogrammica (Brandt) and A. elegantissima (Brandt)." Norton T.R. Fed. Proc. 40:21-25(1981) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 1-28.
[3]	"Leucine 18, a hydrophobic residue essential for high affinity binding of anthopleurin B to the voltage-sensitive sodium channel." Dias-Kadambi B.L., Drum C.L., Hanck D.A., Blumenthal K.M. J. Biol. Chem. 271:9422-9428(1996) [PubMed] [Europe PMC] [Abstract] Cited for: SODIUM CHANNEL-BINDING SITE LEU-18.
[4]	"A specific interaction between the cardiac sodium channel and site-3 toxin anthopleurin B." Benzinger G.R., Kyle J.W., Blumenthal K.M., Hanck D.A. J. Biol. Chem. 273:80-84(1998) [PubMed] [Europe PMC] [Abstract] Cited for: SODIUM CHANNEL-BINDING SITE LYS-37.
[5]	"The role of exposed tryptophan residues in the activity of the cardiotonic polypeptide anthopleurin B." Dias-Kadambi B.L., Combs K.A., Drum C.L., Hanck D.A., Blumenthal K.M. J. Biol. Chem. 271:23828-23835(1996) [PubMed] [Europe PMC] [Abstract] Cited for: SODIUM CHANNEL-BINDING SITE TRP-33.
[6]	"Role of Asn-16 and Ser-19 in anthopleurin B binding. Implications for the electrostatic nature of Na(V) site 3." Seibert A.L., Liu J., Hanck D.A., Blumenthal K.M. Biochemistry 43:7082-7089(2004) [PubMed] [Europe PMC] [Abstract] Cited for: SODIUM CHANNEL-BINDING SITES ASN-16 AND SER-19.
[7]	"Differential phospholipid binding by site 3 and site 4 toxins. Implications for structural variability between voltage-sensitive sodium channel domains." Smith J.J., Alphy S., Seibert A.L., Blumenthal K.M. J. Biol. Chem. 280:11127-11133(2005) [PubMed] [Europe PMC] [Abstract] Cited for: PHOSPHOLIPID-BINDING ACTIVITY.
[8]	"Solution structure of the cardiostimulant polypeptide anthopleurin-B and comparison with anthopleurin-A." Monks S.A., Pallaghy P.K., Scanlon M.J., Norton R.S. Structure 3:791-803(1995) [PubMed] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.

Cross-references

Sequence databases

PIR

NAXAB. A92547.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1APF	NMR	-	A	1-49	[»]

ProteinModelPortal

P01531.

SMR

P01531. Positions 1-49.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Family and domain databases

Gene3D

2.20.20.10. 1 hit.

InterPro

IPR000693. Anenome_toxin.
IPR023355. Myo_neuro_toxin.
[Graphical view]

Pfam

PF00706. Toxin_4. 1 hit.
[Graphical view]

PIRSF

PIRSF001905. Anenome_toxin. 1 hit.

ProtoNet

Search...

Other

EvolutionaryTrace

P01531.

Entry information

Entry name

TXAB_ANTXA

Accession

Primary (citable) accession number: P01531

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	January 1, 1988
Last modified:	May 1, 2013
This is version 84 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program