Q9NII5 (KAX16_MESMA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 1.6 Alternative name(s): BmTX2 Neurotoxin TX2
Organism	Mesobuthus martensii (Manchurian scorpion) (Buthus martensii)
Taxonomic identifier	34649 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Mesobuthus

Protein attributes

Sequence length	58 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	Potent blocker of both large-conductance calcium-activated potassium channels (BKCa channels) and voltage-gated potassium channels (Kv1.3/KCNA3).
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Domain	Has the structural arrangement of an alpha-helix connected to a beta-sheet by disulfide bonds (CSalpha/beta).
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 1 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Molecular function	Ion channel impairing toxin Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond Pyrrolidone carboxylic acid
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological_process	pathogenesis Inferred from electronic annotation. Source: InterPro
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 – 21

21

Ref.3

Chain

22 – 58

37

Potassium channel toxin alpha-KTx 1.6

PRO_0000035318

Sites

Site

48

1

Basic residue of the functional dyad By similarity

Site

57

1

Aromatic residue of the functional dyad By similarity

Amino acid modifications

Modified residue

22

1

Pyrrolidone carboxylic acid

Disulfide bond

28 ↔ 49

Ref.4

Disulfide bond

34 ↔ 54

Ref.4

Disulfide bond

38 ↔ 56

Ref.4

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

58

Helix Strand Turn

Details...

Beta strand

23 – 27

5

Helix

32 – 34

3

Helix

35 – 41

7

Beta strand

47 – 50

4

Beta strand

53 – 56

4

Sequences

	Sequence		Length	Mass (Da)
	Q9NII5 [UniParc]. Last modified October 1, 2000. Version 1. Checksum: F19AA7351B9708B8	FASTA	58	6,507
	10 20 30 40 50 MKISFLLLLA IVICSIGWTE AQFTNVSCSA SSQCWPVCKK LFGTYRGKCM NSKCRCYS

References

[1]	"Genomic organization of three novel toxins from the scorpion Buthus martensi Karsch that are active on potassium channels." Dai L., Wu J.-J., Gu Y.-H., Lan Z.-D., Ling M.-H., Chi C.-W. Biochem. J. 346:805-809(2000) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	"Molecular cloning and genomic organization of a K(+) channel toxin from the Chinese scorpion Buthus martensii Karsch." Zeng X.-C., Zhu Z.-H., Li W.-X., Zhu S.-Y., Peng F., Mao X., Liu H. Toxicon 39:407-410(2001) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA].
[3]	"Purification, characterization, and synthesis of three novel toxins from the Chinese scorpion Buthus martensi, which act on K+ channels." Romi-Lebrun R., Lebrun B., Martin-Eauclaire M.-F., Ishiguro M., Escoubas P., Wu F.Q., Hisada M., Pongs O., Nakajima T. Biochemistry 36:13473-13482(1997) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 22-58, SYNTHESIS, CHARACTERIZATION.
[4]	"Solution structure of two new toxins from the venom of the Chinese scorpion Buthus martensi Karsch blockers of potassium channels." Blanc E., Romi-Lebrun R., Bornet O., Nakajima T., Darbon H. Biochemistry 37:12412-12418(1998) [PubMed] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR OF 22-58, DISULFIDE BONDS.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

AF208300 Genomic DNA. Translation: AAF63972.1.
AF151537 mRNA. Translation: AAQ13576.1.
AF247058 Genomic DNA. Translation: AAK73518.1.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
2BMT	NMR	-	A	23-58	[»]

ProteinModelPortal

Q9NII5.

SMR

Q9NII5. Positions 22-58.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Family and domain databases

Gene3D

3.30.30.10. 1 hit.

InterPro

IPR003614. Scorpion_toxin-like.
IPR001947. Scorpion_toxinS_K_inh.
[Graphical view]

Pfam

PF00451. Toxin_2. 1 hit.
[Graphical view]

PRINTS

PR00286. CHARYBDTOXIN.

ProDom

PD003586. Scorpion_toxinS. 1 hit.
[Graphical view] [Entries sharing at least one domain]

SUPFAM

SSF57095. SSF57095. 1 hit.

PROSITE

PS01138. SCORP_SHORT_TOXIN. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

EvolutionaryTrace

Q9NII5.

Entry information

Entry name

KAX16_MESMA

Accession

Primary (citable) accession number: Q9NII5
Secondary accession number(s): P58489

Entry history

Integrated into UniProtKB/Swiss-Prot:	January 23, 2002
Last sequence update:	October 1, 2000
Last modified:	May 1, 2013
This is version 68 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program