Reviewed, UniProtKB/Swiss-Prot P25687 (MIT1_DENPO)

Names and origin

Protein names	Recommended name:     Toxin MIT1       Short name=MIT 1 Alternative name(s):     Black mamba intestinal toxin 1     Black mamba venom protein A
Organism	Dendroaspis polylepis polylepis (Black mamba)
Taxonomic identifier	8620 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Lepidosauria › Squamata › Scleroglossa › Serpentes › Colubroidea › Elapidae › Elapinae › Dendroaspis

Protein attributes

Sequence length	81 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Potently contracts gastrointestinal (GI) smooth muscle. The receptor for this toxin is present both in the CNS and in the smooth muscle and may be a potassium channel, but not Kv1.1 (KCNA1), Kv1.2 (KCNA2), Kv1.3 (KCNA3), Kv1.4 (KCNA4), Kv1.5 (KCNA5), Kv2.1 (KCNB1), Kv3.4 (KCNC4), Kv4.2 (KCND2), TREK-1 (KCNK2), HERG (KCNH), KCNQ1, KCNQ2, KCNQ3, IRK1 (KCNJ2), IRK2 (KCNJ12), ROMK1 (KCNJ1), GIRK1,2 and GIRK1,4. Ref.1
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Sequence similarities	Belongs to the AVIT (prokineticin) family.

Ontologies

Keywords
Cellular component	Secreted
Molecular function	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
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 81

81

Toxin MIT1

PRO_0000165469

Amino acid modifications

Disulfide bond

7 ↔ 19

Ref.3

Disulfide bond

13 ↔ 31

Ref.3

Disulfide bond

18 ↔ 59

Ref.3

Disulfide bond

41 ↔ 67

Ref.3

Disulfide bond

61 ↔ 77

Ref.3

Natural variations

Natural variant

72

1

P → Q in protein A'.

Experimental info

Sequence conflict

18

1

C → S AA sequence Ref.2

Sequence conflict

22

1

S → C AA sequence Ref.2

Sequence conflict

54

1

R → RK AA sequence Ref.2

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

81

Helix Strand Turn

Details...

Helix

10 – 12

3

Beta strand

17 – 21

5

Beta strand

29 – 33

5

Beta strand

66 – 71

6

Beta strand

74 – 78

5

Sequences

	Sequence		Length	Mass (Da)
	P25687-1 [UniParc]. Last modified July 19, 2005. Version 3. Checksum: 5F6B703434338B03	FASTA	81	8,604
	10 20 30 40 50 60 AVITGACERD LQCGKGTCCA VSLWIKSVRV CTPVGTSGED CHPASHKIPF SGQRMHHTCP 70 80 CAPNLACVQT SPKKFKCLSK S

References

[1]	"MIT1, a black mamba toxin with a new and highly potent activity on intestinal contraction." Schweitz H., Pascaud P., Diochot S., Moinier D., Lazdunski M. FEBS Lett. 461:183-188(1999) [PubMed: 10567694] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION. Tissue: Venom.
[2]	"Snake venom. The amino acid sequence of protein A from Dendroaspis polylepis polylepis (black mamba) venom." Joubert F.J., Strydom D.J. Hoppe-Seyler's Z. Physiol. Chem. 361:1787-1794(1980) [PubMed: 7461607] [Abstract] Cited for: PROTEIN SEQUENCE OF 1-80. Tissue: Venom.
[3]	"A structural homologue of colipase in black mamba venom revealed by NMR floating disulphide bridge analysis." Boisbouvier J., Albrand J.-P., Blackledge M., Jaquinod M., Schweitz H., Lazdunski M., Marion D. J. Mol. Biol. 283:205-219(1998) [PubMed: 9761684] [Abstract] Cited for: STRUCTURE BY NMR OF 1-80, DISULFIDE BONDS. Tissue: Venom.

Cross-references

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1IMT	NMR	-	A	1-80	[»]

ModBase

Search...

Phylogenomic databases

HOVERGEN

P25687.

Family and domain databases

InterPro

IPR009523. Prokineticin.
[Graphical view]

PANTHER

PTHR18821. Prokineticin. 1 hit.

Pfam

PF06607. Prokineticin. 1 hit.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

MIT1_DENPO

Accession

Primary (citable) accession number: P25687

Entry history

Integrated into UniProtKB/Swiss-Prot:	May 1, 1992
Last sequence update:	July 19, 2005
Last modified:	June 16, 2009
This is version 56 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)