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Topic: Conotoxin

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	[No title]
		The cysteine arrangement is the same for omega, delta and kappa families, but omega conotoxins are calcium channel blockers, whereas delta conotoxins delay the inactivation of sodium channels and kappa conotoxins are potassium channel blockers [1].
		Mu conotoxins target the voltage-gated sodium channels [1] and are useful probes for investigating voltage-dependent sodium channels of excitable tissues [4].
		Alpha conotoxins have two types of cysteine arrangement [5] and are competitive nicotinic acetylcholine receptor antagonists.
	www.ebi.ac.uk /interpro/DisplayIproEntry?ac=IPR009958&format=simple (559 words)

	BioMed Central \| Full text \| Structure of alpha-conotoxin BuIA: Influences of disulfide connectivity on structural ...
		The beads form has so far not been reported for naturally occurring conotoxins, but the ribbon connectivity is characteristic of the χ-conotoxins [6,11,12].
		Conotoxins are particularly suitable for structural analysis with NMR spectroscopy because of their small size, solubility and generally well-defined conformations, and the majority of α-conotoxin structures have been determined using this technique [17,18].
		Although the ribbon isomer is less favoured during oxidation, as is often the case for non-native isomers, it displays significantly different properties to both non-native and native conotoxin ribbon isomers.
	www.biomedcentral.com /1472-6807/7/28 (6417 words)

	Reference.com/Encyclopedia/Conotoxin
		Conotoxins, which are peptides consisting of 10 to 30 amino acid residues, typically have some disulfide bonds.
		Conotoxins have a variety of activities, most of which have not been explained closely yet.
		The number of conotoxins whose activities have been determined so far is five, and they are called the α-, δ-, κ-, μ-, and ω types.
	www.reference.com /browse/wiki/Conotoxin (215 words)

	[No title]
		Conotoxin mr5a is the second structure to be solved for the Group II peptides within the M-superfamily of conotoxins.
		Conotoxin mr5a is also of interest because it represents another example of a peptide from Group II of the M-superfamily.
		Conotoxin mr5a is part of the Group II peptides belonging to the M-superfamily because it has a 3-loop arrangement of cystine residues that have a 1-6, 2-4, 3-5 disulfide bond pattern.
	www.sou.edu /chem/faculty/owen/biomr5a.doc (5584 words)

	NationMaster - Encyclopedia: Conotoxin
		A conotoxin is one of a group of neurotoxic peptides isolated from the venom of the marine cone snail.
		Conotoxins, which are peptides consisting of 10 to 30 amino acid residues, typically have some disulfide bonds.
		Each of the five types of conotoxins attacks a different target: α-conotoxin attacks acetylcholine receptors at nerves and muscles, δ-conotoxin inhibits the inactivation of voltage-dependent sodium channels, κ-conotoxin inhibits potassium channels, μ-conotoxin inhibits voltage-dependent sodium ion channels in muscles, and ω-conotoxin inhibits N-type voltage-dependent calcium channels.
	www.nationmaster.com /encyclopedia/Conotoxin (486 words)

	Conotoxin
		Each of the 500 species of cone snail produces roughly 50 to 100 distinct conotoxins which they use to immobilize prey.
		If you have a better definition for Conotoxin than the one presented here, please let us know by making use of the suggest a term option.
		Our attempt is to provide easy definitions on Conotoxin and any other medical topic for the public at large.
	www.medicalglossary.net /Conotoxin.htm (740 words)

	Conotoxin peptides (US5595972)
		The invention is directed to A-lineage conotoxin peptides, which are conotoxin peptides that have strong homology in the signal sequence and the 3'-untranslated region of the genes coding for these peptides to the sequences in the α-conotoxin peptides.
		These latter two conotoxins can be used to diagnose and treat small-cell lung carcinomas, which have cholinergic nicotinic receptors.
		αConotoxin Imperialis I inhibits nicotine evoked hormone release and cell proliferation in human neuroendocrine carcinoma cells.
	www.delphion.com /details?pn=US05595972__ (409 words)

	IngentaConnect Solution structure of an M-1 conotoxin with a novel disulfide lin... (Site not responding. Last check: 2007-10-31)
		The M-superfamily of conotoxins has a typical Cys framework (-CC-C-C-CC-), and is one of the eight major superfamilies found in the venom of the cone snail.
		Recently, two M-1 branch conotoxins (mr3e and tx3a) have been reported to possess a new disulfide bond arrangement between Cys1 and Cys5, Cys2 and Cys4, and Cys3 and Cys6, which is different from those seen in the M-2 and M-4 branches.
		Thus, different disulfide linkages may be employed by conotoxins with the same Cys framework to result in a more diversified backbone scaffold.
	www.ingentaconnect.com /search/article?title=backbone&title_type=tka&year_from=1998&year_to=2006&database=1&pageSize=20&index=14 (306 words)

	Research from the Department of Biology
		Conotoxins are a diverse set of peptide neurotoxins from Conus snail venoms, most of which contain multiple disulfide bonds.
		Formation of the native disulfide bonds during the oxidative folding of conotoxins is prerequisite to proper biological function, but numerous in vitro folding experiments with mature conotoxins have suggested a lack of specificity in the formation of native Cys-Cys connectivities.
		Conotoxins are biosynthesized as precursors, consisting of the N-terminal signal sequence, intervening propeptide and the C-terminal mature conotoxin.
	www.biology.utah.edu /posters2.php?id=40&area=home (510 words)

	Conotoxin Synthesis (Site not responding. Last check: 2007-10-31)
		The formation of the small highly constrained peptide conotoxins with their unusually high density of disulphide bridges is achieved by the folding of the conotoxin as a part of a precursor molecule.
		Once the propeptide molecule has folded, the groups are locked into place, and then the carboxyl end of the peptide is cleaved (cut) to produce a small active toxin with a high density of disulphide bonds.
		Conotoxin precursors are found in the cone shell venom in the form of microscopic granules suspended in the milky fluid.
	grimwade.biochem.unimelb.edu.au /cone/seq_stru.html (239 words)

	Conotoxin - Qwika
		Conotoxin This article or section does not cite...
		A conotoxin is one of a group of neurotoxic...
		of conotoxins attacks a different target: α-conotoxin attacks acetylcholine receptors at nerves and muscles, δ-conotoxin inhibits the inactivation of voltage-dependent sodium channels, κ-conotoxin inhibits potassium channels, μ-conotoxin inhibits...
	www.qwika.com /find/Conotoxin (89 words)

	Some Conotoxin Patents
		a-conotoxins which act at the neuromuscular junction inhibit synaptic transmission by targeting receptors such as the acetylcholine receptor and ion channels.
		In conotoxin GI, U is Glu, V4 is Asn, V5 is Pro, V6 is Ala, W is Gly, X is Arg, Y is His, Z is Tyr, V12 is Ser and R is --NH2.
		Conotoxin MI is identical to GI except that U is Gly-Arg, X is Lys and Y is Asn.
	grimwade.biochem.unimelb.edu.au /cone/conpaten.html (1553 words)

	Pfam 21.0 : Conotoxin (Site not responding. Last check: 2007-10-31)
		Conotoxins are small snail toxins that block ion channels.
		Cone snail toxins, conotoxins, are small neurotoxic peptides with disulfide connectivity that target ion-channels or G-protein coupled receptors.
		Mu conotoxins have two types of cysteine arrangements, but the knottin scaffold is not observed.
	pfam.wustl.edu /cgi-bin/getdesc?name=Conotoxin (257 words)

	Kaleidoscope - UK Research Page 2
		Then the dishes were either set aside for controls or 12.5µL of 50nM Alpha conotoxin MII was added directly to the medium.
		• The specific binding nature of conotoxin MII indicates the a 3 b 2 nicotinic acetylcholine recep- tor is present in DRGs and is possibly being used to monitor and regulate neurite branching of these neurons.
		This indicates that the rate of neu- rite elongation at the growth cones is not significantly inhibited by the increased branch- ing caused by conotoxin.
	www.uky.edu /Kaleidoscope/fall2003/uk-research/page2.htm (854 words)

	A novel conotoxin inhibiting vertebrate voltage-sensitive potassium channels. (Site not responding. Last check: 2007-10-31)
		Based on their pharmacological target (ion channels, receptors) and their disulfide pattern, they have been classified into several toxin families and superfamilies.
		Here, we report a new conotoxin, which is the first member of a structurally new superfamily of Conus peptides and the first conotoxin affecting vertebrate K+ channels.
		The new toxin, designated conotoxin ViTx, has been isolated from the venom of Conus virgo and comprises a single chain of 35 amino acids cross-linked by four disulfide bridges.
	www-ist.cea.fr /publicea/exl-php/00000047605-a-novel-conotoxin-inhibiting-vertebrate-voltage-sensitive-potassium-channels.html (219 words)

	Conotoxin definition - Medical Dictionary definitions of popular medical terms
		Conotoxin: A toxin made by cone snails (Conidae), also called cone shells, which are fish-eating snails that inhabit tropical coral reefs, mangroves and associated habitats.
		Each of the 500 species of cone snail produces roughly 50 to 100 distinct conotoxins which they use to immobilize prey.
		Conotoxins have been used to characterize receptors in heart muscle, skeletal muscle and brain.
	www.medterms.com /script/main/art.asp?articlekey=24864 (151 words)

	Cone snail neurotoxins
		The conotoxins are some of the most potent and diverse neurotoxins known, having an incredibly wide range of actions.
		The alpha conotoxins cause postsynaptic inhibition at the synaptic junction which results in paralysis and death.
		The tissue specific sodium channel blocking mu-conotoxins act primarily upon voltage-sensitive sodium channels in muscle, with only minimal binding to neuronal sodium channels This is unlike tetrodotoxin and saxitoxin which bind to both muscle and nerve sodium channels with equal affinity and independent of voltage.
	www.kingsnake.com /toxinology/conotoxins.html (1611 words)

	Novel excitatory Conus peptides define a new conotoxin superfamily.
		Five peptides that elicited excitatory symptomatology, r11a, r11b, r11c, r11d and r11e, were purified from Conus radiatus venom; four were tested on amphibian peripheral axons and shown to elicit repetitive action potentials, consistent with being members of the 'lightning-strike cabal' of toxins that effect instant immobilization of fish prey.
		A parallel analysis of Conus cDNA clones revealed a new class of conotoxin genes that was particularly enriched (with 18 identified paralogues) in a Conus radiatus venom duct library; several C. radiatus clones encoded the excitatory peptides directly characterized from venom.
		Thus, the I-superfamily conotoxins promise to provide a significant new technology platform for dissecting the molecular components of axons.
	www.galenicom.com /?ac=viewArticleMXPrint&idpm=12694387 (282 words)

	Pain-killer comes out of its shell - Creative & Media - theage.com.au
		Professor Livett says: "Some conotoxins are at least a thousand times more potent than morphine as analgesics, and some may be up to 10,000 times more potent, molecule for molecule.
		While everyone was focusing on omega conotoxins, which block neuronal calcium channel receptors, as potential analgesics, Professor Livett's experience was with nicotinic receptors so he and Dr Khalil, now at National Ageing Research Institute in Parkville, began investigating alpha conotoxins for analgesic activity.
		Elan's Prialt omega conotoxin now offers a superior alternative, but must be injected into the spine because its by-play with receptors in artery walls sends blood pressure soaring into the red zone.
	www.theage.com.au /news/creative--media/painkiller-comes-out-of-its-shell/2005/07/24/1122143728598.html (1310 words)

	Evolutionary Diversification of Multigene Families: Allelic Selection of Toxins in Predatory Cone Snails -- Duda and ...
		Individuals 1, 4, 6, and 9 are homozygous for the uncut allele; individuals 2, 3, 5, 10, and 11 are heterozygous for the cut and uncut alleles; individuals 7 and 8 are homozygous for the cut allele.
		that conotoxins are diversifying between as well as within species.
		A new neurotoxin receptor site on sodium channels is identified by a conotoxin that affects sodium channel inactivation in molluscs and acts as an antagonist in rat brain.
	mbe.oxfordjournals.org /cgi/content/full/17/9/1286 (3266 words)

	delta conotoxin EVIA from Conus ermineus (Site not responding. Last check: 2007-10-31)
		These contribute to an important hydrophobic patch on the surface of the toxin.
		The rest of the structure matches the “ inhibitor cystine-knot motif ” of conotoxins from the "O-superfamily" with a high structural order.
		To probe a possible functional role of the Leu12-Pro13 cis/trans isomerism, a Pro13Ala delta-conotoxin EVIA was synthesized and shown
	sakura.cpe.fr /contributions/EVIA.html (191 words)

	Alpha conotoxin peptides with analgesic properties patent invention (Site not responding. Last check: 2007-10-31)
		[0001] This invention relates to novel peptides of the alpha conotoxin (.alpha.-conotoxin) class and their use in the treatment or prevention of pain, in recovery from nerve injury and in the treatment of painful neurological conditions such as stroke.
		In addition, we have found that a post-translational modification of this peptide lacks analgesic activity but retains the ability of the parent compound to accelerate recovery from nerve injury.
		We have also identified two other new.alpha.-conotoxins, conotoxin An1.1 from Conus anemone and conotoxin Vg1.1 from Conus virgo, which have similar sequences to Vc1.1, and have similar pharmacological actions.
	www.freshpatents.com /Alpha-conotoxin-peptides-with-analgesic-properties-dt20050929ptan20050215480.php (1291 words)

	eMedicine - Conidae : Article by Suzanne M Shepherd, MD, MS, DTMandH
		Almost 200 different conotoxin peptides have been identified to date.
		The venom mixture is specific to each cone shell species, containing 30-200 conotoxin peptides.
		Several conotoxins, and their synthetic derivatives, are the subjects of current clinical trials on chronic pain control, posttraumatic neuroprotection, and the treatment of Parkinson disease and other neuromuscular disorders.
	www.emedicine.com /emerg/topic109.htm (2157 words)

	Novel Interactions Identified between {micro}-Conotoxin and the Na+ Channel Domain I P-loop: Implications for ...
		However, there is no significant coupling between DI-Y401K, which is separated by only one amino acid from residue 403, and Q14R (from Fig.
		(C) Conotoxin GIIIA and GIIIB sensitivities of WT, Y401K, E403K, E758Q, and D1241K channels.
		Topology of the P segments in the sodium channel pore revealed by cysteine mutagenesis.
	www.biophysj.org /cgi/content/full/85/4/2299 (6482 words)

	Diversity of Conus neuropeptides -- Olivera et al. 249 (4966): 257 -- Science
		Efficient oxidative folding of conotoxins and the radiation of venomous cone snails.
		A Novel Conotoxin from Conus betulinus, kappa -BtX, Unique in Cysteine Pattern and in Function as a Specific BK Channel Modulator.
		A conotoxin from Conus textile with unusual posttranslational modifications reduces presynaptic Ca2+ influx.
	www.sciencemag.org /cgi/content/abstract/249/4966/257 (1470 words)

	Toxin Could Be Effective Brain Treatment
		The new toxin - called alpha conotoxin OmIA - was isolated from a cone snail known as conus omaria, whose natural habitat is the Pacific and Indian oceans.
		The OmIA conotoxin is expected to be used in developing numerous new medicines because of its ability to lock on to "nicotinic acetylcholine receptors," which can be found on nerve cells throughout the brain and nervous system.
		University of Utah researchers have found that a nerve toxin used by venomous sea snails can dock with nicotine receptors in the brain, which could lead to new treatments for certain mental illnesses and brain diseases.
	www.scienceagogo.com /news/20060721070022data_trunc_sys.shtml (1369 words)

	FeedNavigator - RSS Mobile (Site not responding. Last check: 2007-10-31)
		Secondary structure formations of conotoxin genes: A possible role in mediating variability..
		Related Articles Secondary structure formations of conotoxin genes: A possible role in mediating variability.
		2006 Aug 23; Authors: Dewan KK Small venomous peptides called conotoxins produced by the predatory marine snail (genus Conus) present an interesting case for mutational studies.
	www.terkko.helsinki.fi /mobile/feednavigator/?articleid=480309 (69 words)

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