Chlorotoxin

Functionⁱ

This toxin binds to the surface of glioma cells, and inhibits their proliferation without having effects on normal brain cells. In this context, this toxin has been described as a chloride channel inhibitor (probably ClC-3/CLCN3) by causing its internalization via caveolae (PubMed:16520829). It has also been described to selectively interact with MMP2 (in complex with MT1-MMP (MMP14) and TIMP2), to inhibit its enzymatic activity and to decrease its presence at the cell surface (PubMed:12454020).3 Publications

Miscellaneous

Does not interact with MMP-1, MMP-3 and MMP-9.1 Publication

GO - Molecular functionⁱ

metalloendopeptidase inhibitor activity Source: UniProtKB-KW
toxin activity Source: UniProtKB-KW

View the complete GO annotation on QuickGO ...

Keywordsⁱ

Molecular function	Chloride channel impairing toxin, Ion channel impairing toxin, Metalloenzyme inhibitor, Metalloprotease inhibitor, Neurotoxin, Protease inhibitor, Toxin, Voltage-gated chloride channel impairing toxin

Molecular function

Chloride channel impairing toxin, Ion channel impairing toxin, Metalloenzyme inhibitor, Metalloprotease inhibitor, Neurotoxin, Protease inhibitor, Toxin, Voltage-gated chloride channel impairing toxin

Names & Taxonomyⁱ

Protein namesⁱ	Recommended name: Chlorotoxin2 Publications Short name: CTX Short name: ClTx1 Publication Alternative name(s): INN: Tozuleristide
Organismⁱ	Leiurus quinquestriatus quinquestriatus (Egyptian scorpion) (Deathstalker scorpion)
Taxonomic identifierⁱ	6885 [NCBI]
Taxonomic lineageⁱ	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Leiurus › Leiurus quinquestriatus

Keywords - Cellular componentⁱ

Secreted

Pathology & Biotechⁱ

Biotechnological useⁱ

Is under phase I clinical trial as BLZ-100 by Blaze Bioscience Inc. as a fluorescent imaging agent that labels tumor tissue to enable more complete and precise surgical resection. BLZ-100 is composed of the chlorotoxin peptide covalently bound to the near-infrared fluorophore indocyanine green.2 Publications

PTM / Processingⁱ

Molecule processing

Feature key	Position(s)	DescriptionActions	Graphical view	Length
PeptideⁱPRO_0000044941	1 – 36	Chlorotoxin1 PublicationAdd BLAST		36

Amino acid modifications

Feature key	Position(s)	DescriptionActions
Disulfide bondⁱ	2 ↔ 19	1 PublicationImported
Disulfide bondⁱ	5 ↔ 28	1 PublicationImported
Disulfide bondⁱ	16 ↔ 33	1 PublicationImported
Disulfide bondⁱ	20 ↔ 35	1 PublicationImported

Keywords - PTMⁱ

Disulfide bond

Expressionⁱ

Tissue specificityⁱ

Expressed by the venom gland.1 Publication

Structureⁱ

Secondary structure

Legend: HelixTurnBeta strandPDB Structure known for this area

Feature key	Position(s)	DescriptionActions	Length
Beta strandⁱ	2 – 4	Combined sources	3
Helixⁱ	12 – 20	Combined sources	9
Beta strandⁱ	22 – 25	Combined sources	4
Beta strandⁱ	26 – 29	Combined sources	4
Beta strandⁱ	32 – 35	Combined sources	4

Show more details

3D structure databases

ProteinModelPortalⁱ	P45639
SMRⁱ	P45639
ModBaseⁱ	Search...
MobiDBⁱ	Search...

Miscellaneous databases

EvolutionaryTraceⁱ	P45639

EvolutionaryTraceⁱ

P45639

Family & Domainsⁱ

Domainⁱ

The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin.1 Publication

Sequence similaritiesⁱ

Belongs to the short scorpion toxin superfamily. Chloride channel inhibitor family.PROSITE-ProRule annotation

Keywords - Domainⁱ

Knottin

Family and domain databases

InterProⁱ	View protein in InterPro IPR036574 Scorpion_toxin-like_sf IPR007958 Scorpion_toxinS_Cl_inh
Pfam protein domain database More...Pfamⁱ	View protein in Pfam PF05294 Toxin_5, 1 hit
SUPFAMⁱ	SSF57095 SSF57095, 1 hit
PROSITEⁱ	View protein in PROSITE PS51200 SHORT_SCORPION_CHLORIDE, 1 hit

Sequenceⁱ

Sequence statusⁱ: Complete.

P45639-1 [UniParc]FASTA Add to basket

« Hide

        10         20         30 
MCMPCFTTDH QMARKCDDCC GGKGRGKCYG PQCLCR

Length:36

Mass (Da):4,005

Last modified:November 1, 1995 - v1

Checksum:ⁱ14A9F57559C6E92A

GO

Sequence databases

PIRⁱ	A48850

PIRⁱ

A48850

Similar proteinsⁱ

50% Identity

Protein	Similar proteins		Species	Score	Length	Source
P45639	Neurotoxin MeuClTx (Fragment)		MESEU		39	UniRef50_P86401
Chlorotoxin-like peptide Bs 14		HOTTS		36
Probable toxin Lqh 8/6		LEIQH		38
Insectotoxin-I5A	)	MESEU		35
Insectotoxin-I3		MESEU		36
+1

Cross-referencesⁱ

Web resourcesⁱ

Wikipedia

Chlorotoxin entry

Sequence databases

PIRⁱ	A48850

PIRⁱ

A48850

3D structure databases

Select the link destinations: Protein Data Bank Europe More...PDBeⁱ Protein Data Bank RCSB More...RCSB PDBⁱ Protein Data Bank Japan More...PDBjⁱ Links Updated	PDB entry	Method	Resolution (Å)	Chain	Positions	PDBsum
	1CHL	NMR	-	A	1-36	[»]
	5L1C	NMR	-	A	1-36	[»]
	6ATW	X-ray	1.53	A	1-36	[»]
ProteinModelPortalⁱ	P45639
SMRⁱ	P45639
ModBaseⁱ	Search...
MobiDBⁱ	Search...

Protocols and materials databases

Structural Biology Knowledgebase	Search...

Structural Biology Knowledgebase

Search...

Miscellaneous databases

EvolutionaryTraceⁱ	P45639

EvolutionaryTraceⁱ

P45639

Family and domain databases

InterProⁱ	View protein in InterPro IPR036574 Scorpion_toxin-like_sf IPR007958 Scorpion_toxinS_Cl_inh
Pfamⁱ	View protein in Pfam PF05294 Toxin_5, 1 hit
SUPFAMⁱ	SSF57095 SSF57095, 1 hit
PROSITEⁱ	View protein in PROSITE PS51200 SHORT_SCORPION_CHLORIDE, 1 hit
ProtoNetⁱ	Search...

Entry informationⁱ

Entry nameⁱ	CTXL_LEIQU
Accessionⁱ	P45639Primary (citable) accession number: P45639
Entry historyⁱ	Integrated into UniProtKB/Swiss-Prot:	November 1, 1995
	Last sequence update:	November 1, 1995
	Last modified:	May 23, 2018
	This is version 84 of the entry and version 1 of the sequence. See complete history.
Entry statusⁱ	Reviewed (UniProtKB/Swiss-Prot)
Annotation program	Animal Toxin Annotation Program

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UniParc

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UniProtKB - P45639 (CTXL_LEIQU)

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<p>This section provides any useful information about the protein, mostly biological knowledge.<p><a href='/help/function_section' target='_top'>More...</a></p>Functioni

Miscellaneous

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Extracellular region or secreted

Extracellular region or secreted

Keywords - Cellular componenti

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Molecule processing

Amino acid modifications

Keywords - PTMi

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Secondary structure

3D structure databases

Miscellaneous databases

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Keywords - Domaini

Family and domain databases

Sequence databases

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Sequence databases

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Keywords - Technical termi

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Functionⁱ

GO - Molecular functionⁱ

Names & Taxonomyⁱ

Subcellular locationⁱ

Keywords - Cellular componentⁱ

Pathology & Biotechⁱ

Biotechnological useⁱ

PTM / Processingⁱ

Keywords - PTMⁱ

Expressionⁱ

Structureⁱ

Family & Domainsⁱ

Sequence similaritiesⁱ

Keywords - Domainⁱ

Cross-referencesⁱ

Web resourcesⁱ

Entry informationⁱ

Miscellaneousⁱ

Keywords - Technical termⁱ