Anemone neurotoxin增殖税
Also known as the sea anemone chrysanthemums, Haidian roots, belonging Coelenterata, Anthozoa,Hexacorallia. Under which three projects, including Actiniaria, Zoanthidea .Ceriantharia. Anemone variety, there are currently more than 1,000 reported species, widely distributed in the world's sea area, China anemone species accounting for the world's 1/10. Anemone tentacles and body contain a lot of stinging cells, where each cell has a special thorn cystic organelles called nematocysts, stored with venom, barbed wire tube coiled in nematocysts, the barbed wire tip of needle. When anemones by external mechanical or chemical stimulation, will release its prey body piercing barbed wire and barbed wire through the tube to inject toxins into the body of the prey, predator or defense in order to achieve the purpose. Research on sea anemone toxin from the 1970s began, has about 40 species of anemones from isolated more than 300 kinds of toxins, according to the molecular weight and different biological functions can be divided into anemone cytol
ytic toxin (molecular weight of about 20 kDa) and the sea anemone polypeptide neurotoxin (MW 3 ~ 7 kDa) into two categories.
Anemone neurotoxin has found more than 70 kinds, according to its role can be divided into different targets three categories, namely the role of the voltage-gated sodium channels (Nav) toxin, a molecular weight of 3 ~ 5 kDa; acting on voltage-gated potassium channels (Kv) toxin, a molecular weight of 3.5 ~ 6.5 kDa; and act on other ion channel polypeptide toxins; addition, there are some anemone polypeptide neurotoxin that specifically act on crustaceans, but not yet know their specific molecular targets.
1.A sea anemone sodium channel toxins
Voltage-gated sodium channels are widely found in animal nervous system, heart, muscles, and other tissues of glial cells. To date by molecular cloning methods have in mammals (including human and mouse) isolated and identified in vivo to a series of sodium channel subtypes are named Nav1.1 ~ Nav1.9 [1]. On the sodium channel in the research process, from a variety of biological molecules as tools sodium channel toxin re
agents greatly promoted to sodium ion channel structure and function of understanding. Anemone sodium channel toxins in the 1970s, was isolated from a sea anemone peptide toxins to a class of molecules, the current through the purification and cloning methods anemones isolated from total more than 50 kinds of sodium channel toxins, Norton, etc. according to The amino acid sequence differences will be divided into three types, namely type 1, type 2 and 3 [2 (] Figure 1). Type 1 and type 2 sodium channel toxins are usually from 46 - 49 amino acid residues, inclusive of six cysteine molecules and the formation of three pairs of disulfide bonds, connection to I-V, II-IV and III- VI. Has been found to have more than 30 kinds of sea anemone sodium channel toxins belong to a type, while belonging to the two sodium channel toxin found only less than 10 kinds. These two types of sodium channel toxin cysteine residues conserved in the sequence distribution, but the level structure and have different characteristics, for example, sodium channel toxin type 1 in the sequence of amino acids with a small number of charges, and two sodium channel toxins are rich in charged amino acid residues, in addition to sodium channel toxin type 2 with charged residues in the sequence were clustered distribution, for example, at the N terminus of a continuous -
Asp-Asp-Asp / Glu-sequence at its C-terminus sequence - Arg-Lys-Lys-Lys-sequence. And a sodium channel toxin is no structural characteristics of this (Figure 1). Although type 1 and type 2 sodium channel toxins in the sequence there is a big difference, but generally agreed that the two sodium channel toxin originated in a common ancestor molecules simultaneously, ISHIDA, etc. from the most primitive of a separate class of anemones Halcurias sp to sodium channels called Halcurin toxins, Halcurin sequences both type 1 and type 2 sodium channel toxin structural features, which further confirms type 1 and type 2 sodium channel toxins have a common ancestor hypothesis [3]. In addition, type 1 and type 2 distribution of sodium channel toxins species-specific, for example, found in the sea anemone Actiniidae there is only one type of sodium channel toxins, and in the column refers to the anemone Branch Stichodactylidae there is both a type 2 sodium channel toxins.
基因甲基化3 type is a class of sodium channel toxin polypeptide toxin relatively short, currently only found five species, usually from 27 to 32 amino acid residues in the molecule and with 8 cysteines form a four pairs of disulfide bonds, but There are exceptions, such as MARTIN
EZ windward anemone Anemonia sulcata from ditch isolated from ATX III containing only three pairs of disulfide bonds. With type 1 and type 2 sodium channel toxins than three sodium channel toxins not only be more number of disulfide bonds, while its cysteine in the sequence distribution is also very different, for example, type 1 and type 2 sodium channel toxins double cysteine (- Cys-Cys-) in the C-terminal sequence, while the 3-type sodium channel toxins - Cys-Cys-located in the N-terminal sequence, which also indicates that three sodium channel toxins may has taken a completely different type 1 and type 2 sodium channel toxin structure motif.
锂合金
Animals and plants there are many natural sodium channel toxins, wherein the sodium channel toxin peptide as strong specificity, high activity, is one of the most interesting study. So far, in mammalian neuronal sodium channel has been found in six parts can be combined with hundreds of toxins. These sites are located outside the cell membrane, the inside passage holes and transmembrane segment. CEST! LE etc. These voltage-gated sodium channels in different parts of the loci were named sites 1 to 6 (site 1 ~ site6), respectively, combined with the toxins in these loci corresponding sites of a toxin copda
alled ~ loci 6 toxins [4]. The current study shows, anemones 1, type 2 and type 3 sodium channel toxins are sodium channel as target loci 3, mode of action is inhibition of the sodium channel inactivation of sodium channels kept leaving open state, thereby makes the action potential duplicate payment, resulting in convulsions prey [4 - 7]. Anemone sodium channel toxins that role model and from scorpion! - Toxins are very similar, but both at the amino acid sequence and spatial structure were not similar, and thus aroused great interest. Currently, the sea anemone sodium channel toxins its high specificity, high affinity and capacity to become study the structure and function of sodium ion channels excellent tool for agents, for example, from the ditch windward anemone toxin ATX II as well as from Huanghai Kui Anthopleura xanthogrammica The ApA and ApB peptide toxins present study sodium channels are a common tool reagents.
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