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Record Information
Version2.0
Creation Date2009-07-03 22:19:09 UTC
Update Date2014-12-24 20:25:39 UTC
Accession NumberT3D2521
Identification
Common NameMaurotoxin
ClassProtein
DescriptionMaurotoxin is a peptide toxin produced by the Chactoid scorpion (Scorpio maurus palmatus). It acts by blocking several types of voltage-gated potassium channel. (3)
Compound Type
  • Amide
  • Amine
  • Animal Toxin
  • Natural Compound
  • Organic Compound
  • Protein
  • Scorpion Toxin
Protein StructureT3d2521
Synonyms
Synonym
MTX
Potassium channel toxin alpha-KTx 6.2
Chemical FormulaNot Available
Average Molecular Mass3621.205 g/mol
CAS Registry Number188240-41-7
SequenceNot Available
Chemical Taxonomy
DescriptionNot Available
KingdomOrganic Compounds
Super ClassOrganic Acids
ClassCarboxylic Acids and Derivatives
Sub ClassAmino Acids, Peptides, and Analogues
Direct ParentPeptides
Alternative ParentsNot Available
SubstituentsNot Available
Molecular FrameworkNot Available
External DescriptorsNot Available
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular LocationsNot Available
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
ApplicationsNot Available
Biological RolesNot Available
Chemical RolesNot Available
Physical Properties
StateLiquid
AppearanceClear solution.
Experimental Properties
PropertyValue
Melting PointNot Available
Boiling PointNot Available
Solubility>10 mg/mL
LogPNot Available
Predicted PropertiesNot Available
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyDeposition DateView
Toxicity Profile
Route of ExposureInjection (sting/bite) (4)
Mechanism of ToxicityMaurotoxin acts by blocking several types of voltage-gated potassium channel. (3)
MetabolismFree toxin may be removed by opsonization via the reticuloendothelial system (primarily the liver and kidneys) or it may be degraded through cellular internalization via the lysosomes. Lysosomes are membrane-enclosed organelles that contain an array of digestive enzymes, including several proteases.
Toxicity ValuesLD50: 9.37 mg/kg (Intravenous, Mouse) (2)
Lethal DoseNot Available
Carcinogenicity (IARC Classification)No indication of carcinogenicity to humans (not listed by IARC).
Uses/SourcesMaurotoxin is a peptide toxin produced by the Chactoid scorpion (Scorpio maurus palmatus). (3)
Minimum Risk LevelNot Available
Health EffectsMaurotoxin is neurotoxic. (3)
SymptomsScorpion stings cause tingling or burning at the site of the sting. In more severe cases, symptoms may include spasm in the throat, feeling of thick tongue, restlessness, muscular fibrillation, abdominal cramps, convulsions, incontinence, hypertension, hypotension, oliguria, cardiac arrhythmias, pulmonary edema, and respiratory failure. (1)
TreatmentNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
DrugBank IDNot Available
HMDB IDNot Available
PubChem Compound IDNot Available
ChEMBL IDNot Available
ChemSpider IDNot Available
KEGG IDNot Available
UniProt IDP80719
OMIM ID
ChEBI IDNot Available
BioCyc IDNot Available
CTD IDNot Available
Stitch IDMaurotoxin
PDB ID1TXM
ACToR IDNot Available
Wikipedia LinkNot Available
References
Synthesis ReferenceNot Available
MSDST3D2521.pdf
General References
  1. Dreisbach, RH (1983). Handbook of Poisoning. Los Altos, California: Lange Medical Publications.
  2. Hassan F (1984). Production of scorpion antivenom. In: Tu AT (ed). Handbook of Toxins. Insects Poisons, Allergens and Other Invertebrate Venoms. Vol. 2. New York: Marcel Dekker.
  3. Wikipedia. Maurotoxin. Last Updated 18 January 2009. [Link]
  4. Wikipedia. Scorpion toxin. Last Updated 12 July 2009. [Link]
Gene Regulation
Up-Regulated GenesNot Available
Down-Regulated GenesNot Available

Targets

General Function:
Protein phosphatase binding
Specific Function:
Forms a voltage-independent potassium channel that is activated by intracellular calcium (PubMed:26148990). Activation is followed by membrane hyperpolarization which promotes calcium influx. Required for maximal calcium influx and proliferation during the reactivation of naive T-cells. The channel is blocked by clotrimazole and charybdotoxin but is insensitive to apamin (PubMed:17157250, PubMed:18796614).
Gene Name:
KCNN4
Uniprot ID:
O15554
Molecular Weight:
47695.12 Da
References
  1. Wikipedia. Maurotoxin. Last Updated 18 January 2009. [Link]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain and the central nervous system, but also in the kidney (PubMed:19903818). Contributes to the regulation of the membrane potential and nerve signaling, and prevents neuronal hyperexcitability (PubMed:17156368). Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:19912772). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, KCNA6, KCNA7, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:12077175, PubMed:17156368). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation of delayed rectifier potassium channels (PubMed:12077175, PubMed:17156368). In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Homotetrameric KCNA1 forms a delayed-rectifier potassium channel that opens in response to membrane depolarization, followed by slow spontaneous channel closure (PubMed:19912772, PubMed:19968958, PubMed:19307729, PubMed:19903818). In contrast, a heterotetrameric channel formed by KCNA1 and KCNA4 shows rapid inactivation (PubMed:17156368). Regulates neuronal excitability in hippocampus, especially in mossy fibers and medial perforant path axons, preventing neuronal hyperexcitability. Response to toxins that are selective for KCNA1, respectively for KCNA2, suggests that heteromeric potassium channels composed of both KCNA1 and KCNA2 play a role in pacemaking and regulate the output of deep cerebellar nuclear neurons (By similarity). May function as down-stream effector for G protein-coupled receptors and inhibit GABAergic inputs to basolateral amygdala neurons (By similarity). May contribute to the regulation of neurotransmitter release, such as gamma-aminobutyric acid (GABA) release (By similarity). Plays a role in regulating the generation of action potentials and preventing hyperexcitability in myelinated axons of the vagus nerve, and thereby contributes to the regulation of heart contraction (By similarity). Required for normal neuromuscular responses (PubMed:11026449, PubMed:17136396). Regulates the frequency of neuronal action potential firing in response to mechanical stimuli, and plays a role in the perception of pain caused by mechanical stimuli, but does not play a role in the perception of pain due to heat stimuli (By similarity). Required for normal responses to auditory stimuli and precise location of sound sources, but not for sound perception (By similarity). The use of toxins that block specific channels suggest that it contributes to the regulation of the axonal release of the neurotransmitter dopamine (By similarity). Required for normal postnatal brain development and normal proliferation of neuronal precursor cells in the brain (By similarity). Plays a role in the reabsorption of Mg(2+) in the distal convoluted tubules in the kidney and in magnesium ion homeostasis, probably via its effect on the membrane potential (PubMed:23903368, PubMed:19307729).
Gene Name:
KCNA1
Uniprot ID:
Q09470
Molecular Weight:
56465.01 Da
References
  1. Wikipedia. Maurotoxin. Last Updated 18 January 2009. [Link]
General Function:
Voltage-gated potassium channel activity
Specific Function:
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain and the central nervous system, but also in the cardiovascular system. Prevents aberrant action potential firing and regulates neuronal output. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:19912772, PubMed:8495559, PubMed:11211111, PubMed:23769686). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, KCNA6, KCNA7, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:8495559, PubMed:20220134). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation of delayed rectifier potassium channels. In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Homotetrameric KCNA2 forms a delayed-rectifier potassium channel that opens in response to membrane depolarization, followed by slow spontaneous channel closure (PubMed:19912772, PubMed:23769686). In contrast, a heteromultimer formed by KCNA2 and KCNA4 shows rapid inactivation (PubMed:8495559). Regulates neuronal excitability and plays a role as pacemaker in the regulation of neuronal action potentials (By similarity). KCNA2-containing channels play a presynaptic role and prevent hyperexcitability and aberrant action potential firing (By similarity). Response to toxins that are selective for KCNA2-containing potassium channels suggests that in Purkinje cells, dendritic subthreshold KCNA2-containing potassium channels prevent random spontaneous calcium spikes, suppressing dendritic hyperexcitability without hindering the generation of somatic action potentials, and thereby play an important role in motor coordination (By similarity). Plays a role in the induction of long-term potentiation of neuron excitability in the CA3 layer of the hippocampus (By similarity). May function as down-stream effector for G protein-coupled receptors and inhibit GABAergic inputs to basolateral amygdala neurons (By similarity). May contribute to the regulation of neurotransmitter release, such as gamma-aminobutyric acid (GABA) (By similarity). Contributes to the regulation of the axonal release of the neurotransmitter dopamine (By similarity). Reduced KCNA2 expression plays a role in the perception of neuropathic pain after peripheral nerve injury, but not acute pain (By similarity). Plays a role in the regulation of the time spent in non-rapid eye movement (NREM) sleep (By similarity).
Gene Name:
KCNA2
Uniprot ID:
P16389
Molecular Weight:
56716.21 Da
References
  1. Wikipedia. Maurotoxin. Last Updated 18 January 2009. [Link]
General Function:
Voltage-gated ion channel activity
Specific Function:
Mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient.
Gene Name:
KCNA3
Uniprot ID:
P22001
Molecular Weight:
63841.09 Da
References
  1. Wikipedia. Maurotoxin. Last Updated 18 January 2009. [Link]
General Function:
Small conductance calcium-activated potassium channel activity
Specific Function:
Forms a voltage-independent potassium channel activated by intracellular calcium. Activation is followed by membrane hyperpolarization. Thought to regulate neuronal excitability by contributing to the slow component of synaptic afterhyperpolarization. The channel is blocked by apamin (By similarity).
Gene Name:
KCNN1
Uniprot ID:
Q92952
Molecular Weight:
59986.87 Da
References
  1. Wikipedia. Maurotoxin. Last Updated 18 January 2009. [Link]
General Function:
Small conductance calcium-activated potassium channel activity
Specific Function:
Forms a voltage-independent potassium channel activated by intracellular calcium. Activation is followed by membrane hyperpolarization. Thought to regulate neuronal excitability by contributing to the slow component of synaptic afterhyperpolarization. The channel is blocked by apamin.
Gene Name:
KCNN2
Uniprot ID:
Q9H2S1
Molecular Weight:
63759.03 Da
References
  1. Wikipedia. Maurotoxin. Last Updated 18 January 2009. [Link]
General Function:
Small conductance calcium-activated potassium channel activity
Specific Function:
Forms a voltage-independent potassium channel activated by intracellular calcium. Activation is followed by membrane hyperpolarization. Thought to regulate neuronal excitability by contributing to the slow component of synaptic afterhyperpolarization. The channel is blocked by apamin.
Gene Name:
KCNN3
Uniprot ID:
Q9UGI6
Molecular Weight:
82025.305 Da
References
  1. Wikipedia. Maurotoxin. Last Updated 18 January 2009. [Link]