|
Hemitoxin
Hemitoxin (HTX; α-KTx6.15) is a 35-mer basic peptide from the venom of the Iranian scorpion ''Hemiscorpius lepturus'', which reversibly blocks Kv1.1, Kv1.2 and Kv1.3 voltage-gated K+ channels. Sources HTX is a neurotoxin derived from the venom of the scorpion ''Hemiscorpius lepturus'', which is found in the southwest province of Iran, Khuzestan. Hemitoxin constitutes about 0.1% of all venom proteins found in the ''Hemiscorpius lepturus'' venom gland. Chemistry HTX is a peptide composed of 35 amino acids including eight cysteine residues which are cross linked forming four intramolecular cystine amino acids via disulfide bridges. It belongs to subfamily 6 of the α-KTx family of potassium channel scorpion toxins and has the highest sequence similarity with Maurotoxin Maurotoxin (abbreviated MTX) is a peptide toxin from the venom of the Tunisian chactoid scorpion '' Scorpio maurus palmatus'', from which it was first isolated and from which the chemical gets its name. It act ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KCNA2
Potassium voltage-gated channel subfamily A member 2 also known as Kv1.2 is a protein that in humans is encoded by the ''KCNA2'' gene. Function Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class, members of which allow nerve cells to efficiently repolarize following an action potential. The coding region of thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KCNA3
Potassium voltage-gated channel, shaker-related subfamily, member 3, also known as KCNA3 or Kv1.3, is a protein that in humans is encoded by the ''KCNA3'' gene. Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes – shaker, shaw, shab, and shal – have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class, members of which allow nerve cells to efficiently repolarize following an action potential. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage-gated Potassium Channel
Voltage-gated potassium channels (VGKCs) are transmembrane channels specific for potassium and sensitive to voltage changes in the cell's membrane potential. During action potentials, they play a crucial role in returning the depolarized cell to a resting state. Classification Alpha subunits Alpha subunits form the actual conductance pore. Based on sequence homology of the hydrophobic transmembrane cores, the alpha subunits of voltage-gated potassium channels are grouped into 12 classes. These are labeled Kvα1-12. The following is a list of the 40 known human voltage-gated potassium channel alpha subunits grouped first according to function and then subgrouped according to the Kv sequence homology classification scheme: Delayed rectifier slowly inactivating or non-inactivating *Kvα1.x - Shaker-related: Kv1.1 (KCNA1), Kv1.2 (KCNA2), Kv1.3 (KCNA3), Kv1.5 (KCNA5), Kv1.6 (KCNA6), Kv1.7 ( KCNA7), Kv1.8 (KCNA10) *Kvα2.x - Shab-related: Kv2.1 (KCNB1), Kv2.2 (KCNB2) *Kvα3.x - ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotoxin
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nervous tissue.Olney 2002 The term can also be used to classify endogenous compounds, which, when abnormally contacted, can prove neurologically toxic. Though neurotoxins are often neurologically destructive, their ability to specifically target neural components is important in the study of nervous systems. Common examples of neurotoxins include lead, ethanol (drinking alcohol), glutamate,Choi 1987 nitric oxide, botulinum toxin (e.g. Botox), tetanus toxin,Simpson 1986 and tetrodotoxin. Some substances such as nitric oxide and glutamate are in fact essential for proper function of the body and only exert neurotoxic effects at excessive concentrations. Neurotoxins inhibit neuron control over ion concentrations across the cell membrane, or com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maurotoxin
Maurotoxin (abbreviated MTX) is a peptide toxin from the venom of the Tunisian chactoid scorpion '' Scorpio maurus palmatus'', from which it was first isolated and from which the chemical gets its name. It acts by blocking several types of voltage-gated potassium channel. Chemistry Maurotoxin is a peptide of 34 amino acids (sequence VSCTGSKDCYAPCRKQTGCPNAKCINKSCKCYGC) cross-linked by four disulfide bridges (Cys3-Cys24, Cys9-Cys29, Cys13-Cys19, Cys31-Cys34), with an atypical pattern of organization compared with other scorpion toxins; this unusual pairing of cysteine residues may be mediated by the presence of adjacent prolines. The peptide contains an alpha helix linked by two disulfide bridges to a two-stranded antiparallel beta sheet. Target Scorpion toxins constitute the largest group of potassium (K+) channel blockers and are useful pharmacological probes to investigate ion channels and their functions. Maurotoxin (MTX) blocks various K+ -channels: * Apamin-sen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scorpio Maurus
''Scorpio maurus'' is a species of North African and Middle Eastern scorpion, also known as the large-clawed scorpion or Israeli gold scorpion and lesser known as Zerachia scorpion. This is a small/medium-sized scorpion from the family Scorpionidae. It has brown back and golden claws. There are many sub-species of this scorpion, 19 of which were described by Fet et al. The venom of ''Scorpio maurus'' contains a high variety of toxins including proteases, phospholipases, protease inhibitors and potassium channel toxins δ-KTx. Although its venom contains a weak neurotoxin called maurotoxin, ''S. maurus'' is not a dangerous scorpion for humans. There are no records of fatalities. Habits Found in very deep burrows in deserts and occasionally sparse woodland. Its habit of creating very deep burrows (up to 1 metre deep) means that in captivity this scorpion is often happiest with higher humidity Humidity is the concentration of water vapor present in the air. Water vapo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Channel Toxins
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons. Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
