Reviewed, UniProtKB/Swiss-Prot Q9U8D2 (KAX82_MESMA)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 8.2 Alternative name(s):     Neurotoxin BmP01     Potassium ion channel blocker P01
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	57 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	Blocks small conductance calcium-activated potassium channels (KCNN, SK). Low toxicity by intracerebroventricular injection into mice.
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 8 subfamily.
Mass spectrometry	Molecular mass is 3177.47 Da from positions 29 - 57. Determined by MALDI. Ref.3 Molecular mass is 3177 Da from positions 29 - 57. Determined by ESI. Ref.4

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Molecular function	Ionic channel inhibitor Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological process	pathogenesis Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	potassium 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 – 28

28

Ref.3 Ref.4

Peptide

29 – 57

29

Potassium channel toxin alpha-KTx 8.2 Ref.3

PRO_0000035348

Amino acid modifications

Disulfide bond

31 ↔ 47

Ref.4

Disulfide bond

34 ↔ 52

Ref.4

Disulfide bond

38 ↔ 54

Ref.4

Experimental info

Sequence conflict

17

1

V → I in AAF24057. Ref.2

Sequence conflict

21

1

T → I in AAF24057. Ref.2

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

57

Helix Strand Turn

Details...

Helix

31 – 33

3

Turn

35 – 42

8

Beta strand

44 – 46

3

Beta strand

48 – 51

4

Beta strand

53 – 55

3

Sequences

	Sequence		Length	Mass (Da)
	Q9U8D2-1 [UniParc]. Last modified May 1, 2000. Version 1. Checksum: 4265970F1250B53A	FASTA	57	6,318
	10 20 30 40 50 MSRLYAIILI ALVFNVVMTI TPDMKVEAAT CEDCPEHCAT QNARAKCDND KCVCEPK

References

[1]	"Genomic organization of three neurotoxins active on small conductance Ca2+-activated potassium channels from the scorpion Buthus martensi Karsch." Wu J.-J., Dai L., Lan Z.-D., Chi C.-W. FEBS Lett. 452:360-364(1999) [PubMed: 10386622] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Tissue: Venom gland.
[2]	"Molecular characterization of a K+ channel blocker from Buthus martensii." Zhu S.-Y., Zeng X.-C., Li W.-X., Jiang D.-H. Kexue Tongbao 44:2295-2299(1999) Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom gland.
[3]	"Characterization of four toxins from Buthus martensi scorpion venom, which act on apamin-sensitive Ca2+-activated K+ channels." Romi-Lebrun R., Martin-Eauclaire M.-F., Escoubas P., Wu F.Q., Lebrun B., Hisada M., Nakajima T. Eur. J. Biochem. 245:457-464(1997) [PubMed: 9151979] [Abstract] Cited for: PROTEIN SEQUENCE OF 29-57, MASS SPECTROMETRY.
[4]	"Solution structure of BmP01 from the venom of scorpion Buthus martensii Karsch." Wu G., Li Y., Wei D., He F., Jiang S., Hu G., Wu H. Biochem. Biophys. Res. Commun. 276:1148-1154(2000) [PubMed: 11027603] [Abstract] Cited for: PROTEIN SEQUENCE OF 29-38, STRUCTURE BY NMR OF 29-57, DISULFIDE BONDS, MASS SPECTROMETRY.

Cross-references

Sequence databases

EMBLGenBankDDBJ

AF095781 Genomic DNA. Translation: AAF03045.1.
AF114024 mRNA. Translation: AAF24057.1.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1WM7	NMR	-	A	29-57	[»]

ModBase

Search...

Family and domain databases

InterPro

IPR008911. Toxin_6.
[Graphical view]

Pfam

PF05453. Toxin_6. 1 hit.
[Graphical view]

PROSITE

PS01138. SCORP_SHORT_TOXIN. False negative.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

KAX82_MESMA

Accession

Primary (citable) accession number: Q9U8D2
Secondary accession number(s): Q9U522

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 19, 2001
Last sequence update:	May 1, 2000
Last modified:	November 24, 2009
This is version 49 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)