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Pandinus Imperator (Pi3) Toxin
Pi3 toxin is a purified peptide derivative of the Emperor scorpion, ''Pandinus imperator'' scorpion venom. It is a potent blocker of voltage-gated potassium channel, KCNA3, Kv1.3 and is closely related to another peptide found in the venom, Pi2. Etymology & source Etymology Pi3 toxin stands for ''Pandinus imperator''-3 toxin. It is also known as pandinotoxin-beta and toxin PiTX-K-beta. The classification of the short peptide toxins is based on the conserved cysteine residues and the phylogenetic analysis of the aminoacid sequence. Miller was the one who first used aminoacid sequence to classify these toxins and he assigned the nomenclature α-KTxm.n where m indicates the subfamily and n indicates the member within the subfamily. Pi3 thus got the name α-KTx7.2. The subfamily 7 has one other member, Pi2. Sources The Pi3 toxin is found in the venom of the ''Pandinus imperator'' scorpion. It belongs to a family of toxins known as α-KTx. Several peptides, named Pi1-Pi7 were puri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3D Structure Of Pi3 Toxin
3-D, 3D, or 3d may refer to: Science, technology, and mathematics Relating to three-dimensionality * Three-dimensional space ** 3D computer graphics, computer graphics that use a three-dimensional representation of geometric data ** 3D film, a motion picture that gives the illusion of three-dimensional perception ** 3D modeling, developing a representation of any three-dimensional surface or object ** 3D printing, making a three-dimensional solid object of a shape from a digital model ** 3D display, a type of information display that conveys depth to the viewer ** 3D television, television that conveys depth perception to the viewer ** Stereoscopy, any technique capable of recording three-dimensional visual information or creating the illusion of depth in an image Other uses in science and technology or commercial products * 3D projection * 3D rendering * 3D scanning, making a digital representation of three-dimensional objects * 3D video game (other) * 3-D Secure, a se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
310 Helix
A 310 helix is a type of secondary structure found in proteins and polypeptides. Of the numerous protein secondary structures present, the 310-helix is the fourth most common type observed; following α-helices, β-sheets and reverse turns. 310-helices constitute nearly 10–15% of all helices in protein secondary structures, and are typically observed as extensions of α-helices found at either their N- or C- termini. Because of the α-helices tendency to consistently fold and unfold, it has been proposed that the 310-helix serves as an intermediary conformation of sorts, and provides insight into the initiation of α-helix folding. Discovery Max Perutz, the head of the Medical Research Council Laboratory of Molecular Biology at the University of Cambridge, wrote the first paper documenting the elusive 310-helix. Together with Lawrence Bragg and John Kendrew, Perutz published an exploration of polypeptide chain configurations in 1950, based on cues from noncrystalline diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BK Channel
BK channels (big potassium), are large conductance calcium-activated potassium channels, also known as Maxi-K, slo1, or Kca1.1. BK channels are voltage-gated potassium channels that conduct large amounts of potassium ions (K+) across the cell membrane, hence their name, ''big potassium''. These channels can be activated (opened) by either electrical means, or by increasing Calcium in biology, Ca2+ concentrations in the cell. BK channels help regulate physiological processes, such as Circadian rhythm, circadian behavioral rhythms and neuronal excitability. BK channels are also involved in many processes in the body, as it is a ubiquitous channel. They have a tetrameric structure that is composed of a transmembrane domain, voltage sensing domain, potassium channel domain, and a cytoplasmic C-terminal domain, with many X-ray structures for reference. Their function is to repolarize the membrane potential by allowing for potassium to flow outward, in response to a depolarization ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissociation Constant
In chemistry, biochemistry, and pharmacology, a dissociation constant (K_D) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions. The dissociation constant is the inverse of the association constant. In the special case of salts, the dissociation constant can also be called an ionization constant. For a general reaction: : A_\mathit B_\mathit \mathit A + \mathit B in which a complex \ce_x \ce_y breaks down into ''x'' A subunits and ''y'' B subunits, the dissociation constant is defined as : K_D = \frac where and ''x'' B''y''are the equilibrium concentrations of A, B, and the complex A''x'' B''y'', respectively. One reason for the popularity of the dissociation constant in biochemistry and pharmacology is that in the frequently encount ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissociation Constant
In chemistry, biochemistry, and pharmacology, a dissociation constant (K_D) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions. The dissociation constant is the inverse of the association constant. In the special case of salts, the dissociation constant can also be called an ionization constant. For a general reaction: : A_\mathit B_\mathit \mathit A + \mathit B in which a complex \ce_x \ce_y breaks down into ''x'' A subunits and ''y'' B subunits, the dissociation constant is defined as : K_D = \frac where and ''x'' B''y''are the equilibrium concentrations of A, B, and the complex A''x'' B''y'', respectively. One reason for the popularity of the dissociation constant in biochemistry and pharmacology is that in the frequently encount ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spodoptera Frugiperda
The fall armyworm (''Spodoptera frugiperda'') is a species in the order Lepidoptera and one of the species of the fall armyworm moths distinguished by their larval life stage. The term "armyworm" can refer to several species, often describing the large-scale invasive behavior of the species' larval stage. It is regarded as a pest and can damage and destroy a wide variety of crops, which causes large economic damage. Its scientific name derives from ''frugiperda,'' which is Latin for ''lost fruit'', named because of the species' ability to destroy crops. Because of its propensity for destruction, the fall armyworm's habits and possibilities for crop protection have been studied in depth. It is also a notable case for studying sympatric speciation, as it appears to be diverging into two species currently. Another remarkable trait of the larva is that they consistently practice cannibalism, despite its fitness costs. The fall armyworm is active at a different time of year from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sf9 (cells)
Sf9 cells, a clonal isolate of ''Spodoptera frugiperda'' Sf21 cells (IPLB-Sf21-AE), are commonly used in insect cell culture for recombinant protein production using baculovirus. They were originally established from ovarian tissue. They can be grown in the absence of serum, and can be cultured attached or in suspension. Sf9 Rhabdovirus It has previously been shown that some Sf9 cell lines harbor a negative sense Rhabdovirus called Spodoptera frugiperda rhabdovirus ''Spodoptera'' is a genus of moths of the family Noctuidae erected by Achille Guenée in 1852. Many are known as pest insects. The larvae are sometimes called armyworms. The roughly thirty species are distributed across six continents. Descri ... (SfRV). However, not all tested Sf9 cells appear to be infected with this virus. SfRV appears to be insect-specific and does not appear to infect mammalian cell lines.{{cite journal, author=Maghodia AB, Jarvis DL, title=Infectivity of Sf-rhabdovirus variants in i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shaker Gene
The ''shaker (Sh)'' gene, when mutated, causes a variety of atypical behaviors in the fruit fly, ''Drosophila melanogaster''. Under ether anesthesia, the fly’s legs will shake (hence the name); even when the fly is unanaesthetized, it will exhibit aberrant movements. Sh-mutant flies have a shorter lifespan than regular flies; in their larvae, the repetitive firing of action potentials as well as prolonged exposure to neurotransmitters at neuromuscular junctions occurs. In ''Drosophila'', the shaker gene is located on the X chromosome. The closest human homolog is KCNA3. Function The ''Sh'' gene plays a part in the operation of potassium ion channels, which are integral membrane proteins and are essential to the correct functioning of the cell. A working shaker channel is voltage-dependent and has four subunits, which form a pore through which ions flow, carrying type-A potassium current (IA). A mutation in the Sh gene reduces the conductance of charge across the neuron si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Helix
The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues earlier along the protein sequence. The alpha helix is also called a classic Pauling–Corey–Branson α-helix. The name 3.613-helix is also used for this type of helix, denoting the average number of residues per helical turn, with 13 atoms being involved in the ring formed by the hydrogen bond. Among types of local structure in proteins, the α-helix is the most extreme and the most predictable from sequence, as well as the most prevalent. Discovery In the early 1930s, William Astbury showed that there were drastic changes in the X-ray fiber diffraction of moist wool or hair fibers upon significant stretching. The data suggested that the unstretched fibers had a coiled molecular structure with a characteristic repeat of ≈. Astb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charybdotoxin
Charybdotoxin (CTX) is a 37 amino acid neurotoxin from the venom of the scorpion '' Leiurus quinquestriatus hebraeus'' (''deathstalker'') that blocks calcium-activated potassium channels. This blockade causes hyperexcitability of the nervous system. It is a close homologue of agitoxin and both toxins come from ''Leiurus quinquestriatus hebraeus''. It is named after Charybdis, a sea monster from Greek myth. Chemical properties Family The Charybdotoxin family of scorpion toxins is a group of small peptides that has many family members, such as the pandinotoxin, derived from the venom of scorpion Pandinus imperator. Structure Scorpions such as the deathstalker paralyze their prey by injecting a potent mix of peptide toxins. Charybdotoxin, a 37 amino acid, 4 kDa neurotoxin with the molecular formula C176H277N57O55S7, is one of the peptide toxins that can be extracted from the venom of the scorpion. Its structure is very similar to that of margatoxin. Charybdotoxin contains three d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emperor Scorpion
The emperor scorpion, ''Pandinus imperator'', is a species of scorpion native to rainforests and savannas in West Africa. It is one of the largest scorpions in the world and lives for 6–8 years. Its body is black, but like other scorpions it glows pastel green or blue under ultraviolet light. It is a popular species in the pet trade, and is protected by CITES to prevent over-collecting that might impact the species' survival. Description The emperor scorpion (''Pandinus imperator'') is one of the largest species of scorpion in the world, with adults averaging about in length and a weight of 30 g. However, some species of forest scorpions are fairly similar to the emperor scorpion in size, and one scorpion, ''Heterometrus swammerdami'', holds the record for being the world's largest scorpion at 9 inches (23 cm) in length. The large pincers are blackish-red and have a granular texture. The front part of the body, or prosoma, is made up of four sections, each with a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gel Filtration Chromatography
Size-exclusion chromatography (SEC), also known as molecular sieve chromatography, is a chromatographic method in which molecules in solution are separated by their size, and in some cases molecular weight. It is usually applied to large molecules or macromolecular complexes such as proteins and industrial polymers. Typically, when an aqueous solution is used to transport the sample through the column, the technique is known as gel-filtration chromatography, versus the name gel permeation chromatography, which is used when an organic solvent is used as a mobile phase. The chromatography column is packed with fine, porous beads which are commonly composed of dextran, agarose, or polyacrylamide polymers. The pore sizes of these beads are used to estimate the dimensions of macromolecules. SEC is a widely used polymer characterization method because of its ability to provide good molar mass distribution (Mw) results for polymers. Applications The main application of gel-filtration chro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
