O77091 (SIXP_MESMA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Beta-insect excitatory toxin BmK IT-AP

Alternative name(s):
Bm33-I
BmKITAP
Insect toxin analgesic peptide

Gene names

Name:

IT-AP

Organism

Mesobuthus martensii (Manchurian scorpion) (Buthus martensii)

Taxonomic identifier

34649 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Mesobuthus

Protein attributes

Sequence length	90 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Excitatory insect beta-toxins induce a spastic paralysis. They bind voltage-independently at site-4 of sodium channels and shift the voltage of activation toward more negative potentials thereby affecting sodium channel activation and promoting spontaneous and repetitive firing. This insect toxin is also active on mice, showing an analgesic effect.
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Toxic dose	PD50 is 0.49 ng/mg in gryllus bimaculatus crickets. Ref.3
Sequence similarities	Belongs to the long (4 C-C) scorpion toxin superfamily. Sodium channel inhibitor family. Beta subfamily.
Mass spectrometry	Molecular mass is 8149.39 Da from positions 19 - 90. Determined by MALDI. Ref.3

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Molecular function	Ionic channel inhibitor Neurotoxin Sodium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological process	defense response Inferred from electronic annotation. Source: InterPro
Cellular component	extracellular region 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

Signal peptide

1 – 18

18

Ref.1 Ref.3

Chain

19 – 90

72

Beta-insect excitatory toxin BmK IT-AP

PRO_0000035211

Amino acid modifications

Disulfide bond

34 ↔ 55

Ref.4

Disulfide bond

40 ↔ 60

Ref.4

Disulfide bond

44 ↔ 62

Ref.4

Disulfide bond

56 ↔ 82

Ref.4

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

90

Helix Strand Turn

Details...

Beta strand

20 – 25

6

Helix

37 – 48

12

Beta strand

51 – 56

6

Beta strand

59 – 65

7

Helix

76 – 83

8

Sequences

	Sequence		Length	Mass (Da)
	O77091 [UniParc]. Last modified November 1, 1998. Version 1. Checksum: ED240D0BCF637EA2	FASTA	90	10,225
	10 20 30 40 50 60 MKFFLIFLVI FPIMGVLGKK NGYAVDSSGK VAECLFNNYC NNECTKVYYA DKGYCCLLKC 70 80 90 YCFGLADDKP VLDIWDSTKN YCDVQIIDLS

References

[1]	"Molecular characterization of a new excitatory insect neurotoxin with an analgesic effect on mice from the scorpion Buthus martensi Karsch." Xiong Y.-M., Lan Z.-D., Wang M., Liu B., Liu X.-Q., Fei H., Xu L.-G., Xia Q.-C., Wang C.-G., Wang D.-C., Chi C.-W. Toxicon 37:1165-1180(1999) [PubMed: 10400300] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], PROTEIN SEQUENCE OF 19-90. Tissue: Venom and Venom gland.
[2]	Li W., Zhu S. Submitted (JUN-1999) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom gland.
[3]	"Sequence and electrophysiological characterization of two insect-selective excitatory toxins from the venom of the Chinese scorpion Buthus martensi." Escoubas P., Stankiewicz M., Takaoka T., Pelhate M., Romi-Lebrun R., Wu F.Q., Nakajima T. FEBS Lett. 483:175-180(2000) [PubMed: 11042276] [Abstract] Cited for: PROTEIN SEQUENCE OF 19-90, ELECTROPHYSIOLOGICAL CHARACTERIZATION, PARALYTIC DOSE, MASS SPECTROMETRY. Tissue: Venom.
[4]	"Crystallization and preliminary X-ray analyses of insect neurotoxins with analgesic effect from the scorpion Buthus martensii Karsch." Guan R.J., Liu X.Q., Liu B., Wang M., Wang D.C. Acta Crystallogr. D 56:1012-1014(2000) [PubMed: 10944339] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS) OF 19-90, DISULFIDE BONDS.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

AF055672 Genomic DNA. Translation: AAC61256.1.
AF156171 mRNA. Translation: AAF29464.1.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1T0Z	X-ray	2.60	A/B	19-90	[»]

ProteinModelPortal

O77091.

SMR

O77091. Positions 19-90.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Family and domain databases

InterPro

IPR003614. Knot1.
IPR002061. Scorpion_toxin_lc.
[Graphical view]

Pfam

PF00537. Toxin_3. 1 hit.
[Graphical view]

SMART

SM00505. Knot1. 1 hit.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

SIXP_MESMA

Accession

Primary (citable) accession number: O77091

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 7, 2004
Last sequence update:	November 1, 1998
Last modified:	November 16, 2011
This is version 58 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program