P83407 (KA191_MESMA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 19.1 Alternative name(s): BmK37 Neurotoxin BmBKTx1
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	31 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Selective inhibitor of high conductance calcium-activated potassium channels KCa1.1/KCNMA1. May be insect specific. Ref.1 Ref.2
Subunit structure	Monomer. Ref.1
Subcellular location	Secreted Ref.1.
Tissue specificity	Expressed by the venom gland. Ref.1
Domain	Has the structural arrangement of an alpha-helix connected to a beta-sheet by disulfide bonds (CSalpha/beta).
Miscellaneous	Has no effect on voltage-gated potassium channels Kv1.1/KCNA1, Kv1.2/KCNA2, Kv1.3/KCNA3, Kv11.1/KCNH2, Kv11.2/KCNH6, Kv11.3/KCNH7, Kv7.1/KCNQ1 and on Kir2.1/KCNJ2 (Ref.2).
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 19 subfamily.
Mass spectrometry	Molecular mass is 3335.14 Da from positions 1 - 31. Determined by MALDI. Ref.1

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ion channel impairing toxin 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: 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

Peptide

1 – 31

31

Potassium channel toxin alpha-KTx 19.1

PRO_0000044898

Sites

Site

9

1

Crucial for toxin binding Probable

Site

11

1

Crucial for toxin binding Probable

Site

21

1

Basic residue of the functional dyad By similarity

Site

30

1

Aromatic residue of the functional dyad By similarity

Amino acid modifications

Disulfide bond

3 ↔ 22

Ref.1 Ref.3

Disulfide bond

8 ↔ 27

Ref.1 Ref.3

Disulfide bond

12 ↔ 29

Ref.1 Ref.3

Secondary structure

1

.

.

.

.

.

.

.

31

Helix Strand Turn

Details...

Helix

5 – 14

10

Beta strand

18 – 23

6

Beta strand

26 – 30

5

Sequences

	Sequence		Length	Mass (Da)
	P83407 [UniParc]. Last modified October 1, 2002. Version 1. Checksum: FD13B6FDB90746F1	FASTA	31	3,342
	10 20 30 AACYSSDCRV KCVAMGFSSG KCINSKCKCY K

References

[1]	Xu C.-Q., Chi C.-W. Submitted (JUL-2002) to UniProtKB Cited for: PROTEIN SEQUENCE, FUNCTION, SUBUNIT, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, MASS SPECTROMETRY, DISULFIDE BONDS. Tissue: Venom.
[2]	"BmBKTx1, a novel Ca2+-activated K+ channel blocker purified from the Asian scorpion Buthus martensi Karsch." Xu C.-Q., Brone B., Wicher D., Bozkurt O., Lu W.-Y., Huys I., Han Y.-H., Tytgat J., Van Kerkhove E., Chi C.-W. J. Biol. Chem. 279:34562-34569(2004) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE, SYNTHESIS, FUNCTION. Tissue: Venom.
[3]	"Solution structure of BmBKTx1, a new BKCa1 channel blocker from the Chinese scorpion Buthus martensi Karsch." Cai Z., Xu C.-Q., Xu Y., Lu W., Chi C.-W., Shi Y., Wu J. Biochemistry 43:3764-3771(2004) [PubMed] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.
[4]	"Structure of the scorpion toxin BmBKTtx1 solved from single wavelength anomalous scattering of sulfur." Szyk A., Lu W.-Y., Xu C.-Q., Lubkowski J. J. Struct. Biol. 145:289-294(2004) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (1.72 ANGSTROMS) OF 2-30.
+	Additional computationally mapped references.

Cross-references

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1Q2K	NMR	-	A	1-31	[»]
1R1G	X-ray	1.72	A/B	1-31	[»]
3E8Y	X-ray	1.10	X	1-31	[»]

ProteinModelPortal

P83407.

SMR

P83407. Positions 1-31.

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]

SUPFAM

SSF57095. SSF57095. 1 hit.

PROSITE

PS01138. SCORP_SHORT_TOXIN. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

EvolutionaryTrace

P83407.

Entry information

Entry name

KA191_MESMA

Accession

Primary (citable) accession number: P83407

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 2002
Last sequence update:	October 1, 2002
Last modified:	May 1, 2013
This is version 54 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program