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商品详细Smartox/阻断nAChR/08CON012-00500/0.5mg肌型的α/δ部位
Smartox/阻断nAChR/08CON012-00500/0.5mg肌型的α/δ部位
Smartox/阻断nAChR/08CON012-00500/0.5mg肌型的α/δ部位
商品编号: 08CON012-00500
品牌: smartox-biotech
市场价: ¥1872.00
美元价: 1440.00
产地: 美国(厂家直采)
公司:
产品分类: 酸碱缓冲液
公司分类: acid_base_buffer_solution
联系Q Q: 3392242852
电话号码: 4000-520-616
电子邮箱: info@ebiomall.com
商品介绍

α-conotoxinMI (alpha-conotoxinMI)isaconotoxinthathasbeenisolatedfromthevenomoftheconesnailConusmagus. α-conotoxinMIisacompetitiveantagoNISTofthemuscle-typenicotinicacetylcholinereceptors(nAChR)suchas α-conotoxinGIord-Turbocurarine.ItbindstothereceptorwithaKdvalue~0,94nM. α-conotoxinMIallowstodistinguishbetweenthetwoagonistsitesasitbinds10,000-foldmoretightlytotheα/δthantotheα/γsite.


Description:

Productcode:08CON012.Category:NicotinicAcetylcholineReceptor.Tags:83481-45-2,bungarotoxin,nachr,nicotinic.

AAsequence: Gly-Arg-Cys3-Cys4-His-Pro-Ala-Cys8-Gly-Lys-Asn-Tyr-Ser-Cys14-NH2
Disulfidebonds: Cys3-Cys8 andCys4-Cys14
Length(aa): 14
Formula: C58H88N22O17S4
MolecularWeight: 1495.08Da
Appearance:Whitelyophilizedsolid
Solubility: waterorsalinebuffer
CASnumber: [83481-45-2]Source: Synthetic
Purityrate: >97%

Reference:

Criticalresiduesinfluencetheaffinityandselectivityofalpha-conotoxinMIfornicotinicacetylcholinereceptors

Themammalianskeletalmuscleacetylcholinereceptorcontainstwononequivalentacetylcholinebindingsites,oneeachatthealpha/deltaandalpha/gammasubunitinterfaces.Alpha-ConotoxinMI,a14-aminoacidcompetitiveantagonist,bindsatbothinterfacesbuthasapproximately10(4)higheraffinityforthealpha/deltasite.Weperformedan“alaninewalk”toidentifytheresiduesinalpha-MIthatcontributetothisselectiveinteractionwiththealpha/deltasite.ElectrophysiologicalmeasurementswithXenopusoocytesexpressingnormalreceptorsorreceptorslackingeitherthegammaordeltasubunitweremadetoassaytoxin-receptorinteraction.Alaninesubstitutionsinmostaminoacidpositionshadonlymodesteffectsontoxinpotencyateitherbindingsite.However,substitutionsintwopositions,proline-6andtyrosine-12,dramaticallyreducedtoxinpotencyatthehigh-affinityalpha/deltasitewhilehavingcomparativelylittleeffectonlow-affinityalpha/gammabinding.Whentyrosine-12wasreplacedbyalanine,thetoxin’sselectivityforthehigh-affinitysite(relativetothatforthelow-affinitysite)wasreducedfrom45,000-to30-fold.Aseriesofadditionalaminoacidsubstitutionsinthispositionshowedthatincreasingsidechainsize/hydrophobicityincreasestoxinpotencyatthealpha/deltasitewithoutaffectingalpha/gammabinding.Incontrast,whentyrosine-12isdiiodinated,toxinbindingisnearlyirreversIBLeatthealpha/deltasitebutalsoincreasesbyapproximately500-foldatthealpha/gammasite.Theeffectsofposition12substitutionsareaccountedforalmostentirelybychangesintherateoftoxindissociationfromthehigh-affinityalpha/deltabindingsite.

Jacobsen,R.B., etal.(1999) Criticalresiduesinfluencetheaffinityandselectivityofalpha-conotoxinMIfornicotinicacetylcholinereceptors, Biochemistry. PMID:10529206

ConotoxinMI.Disulfidebondingandconformationalstates
ThetoxicpeptidefromConusmagusvenom(conotoxinMI)isa14-aminoacidpeptide(McIntosh,M.,Cruz,L.J.,Hunkapiller,M.W.,Gray,W.R.,andOlivera,B.M.(1982)Arch.Biochem.Biophys.218,329-334)whichinhibitstheacetylcholinereceptor.Inthisworkwehaveconfirmedtheprimarystructureandestablishedthedisulfidebondingconfiguration(Cys3-Cys8;Cys4-Cys14)bydirectchemicalsynthesisofthetoxinwithspecificdisulfidebridges.Naturalandsynthetictoxinswerecomparedbyseveralmethods.Fastatombombardmentmassspectroscopyconfirmedthatthesyntheticproducthadtheexpectedmolecularmassandnumberofexchangeablehydrogens.UltravioletCDspectrawerecloselycomparableinshapeandmagnitudeforthetwomaterials,whichwerealsoidenticalinBIOLOGicalactivityandchromatographicbehavior.Wehavealsoestablishedthat,althoughthepeptideishighlycross-linkedwithtwodisulfidebridges,itcanslowlyequilibratebetweentwoconformations.Asimulationanalysissuggeststhattheconformershavehalf-livesofapproximately12andapproximately72minat0degreesC,decreasingapproximately2-foldforevery10degreesCincreaseintemperature.

Gray,W.R., etal.(1983) ConotoxinMI.Disulfidebondingandconformationalstates, JBiolChem. PMID:6630187

Site-specificchargeinteractionsofalpha-conotoxinMIwiththenicotinicacetylcholinereceptor
Wehavetestedtheimportanceofchargeinteractionsforalpha-conotoxinMIbindingtothenicotinicacetylcholinereceptor(AChR).Ionicresiduesonalpha-conotoxinMIwerealteredbysite-directedmutagenesisorbychemicalmodification.Inphysiologicalbuffer,removalofchargesattheNterminus,His-5,andLys-10hadsmall(2-4-fold)effectsonbindingaffinitytothemousemuscleAChRandtheTorpedoAChR.Itwasalsodemonstratedthatconotoxinhadnoeffectontheconformationalequilibriumofeitherreceptor,asassessedbytheeffectsofthenoncompetitiveantagonistproADIfenonconotoxinbindingand,conversely,theeffectofconotoxinontheaffinityofphencyclidine,proadifen,andethidium.Conotoxindisplayedhigherbindingaffinityinlowionicstrengthbuffer;neutralizationofLys-10andtheNterminusbyacetylationblockedthisaffinityshiftatthealphadeltasitebutnotatthealphagammasite.ItisconcludedthatCtxresiduesLys-10andtheNterminalinteractwithoppositelychargedreceptorresiduesonlyatthealphadeltasite,andthetwositeshavedistinctarrangementsofchargedresidues.Ethidiumfluorescenceexperimentsdemonstratedthatconotoxinisformallycompetitivewithasmallcholinergicligand,tetramethylammonium.Thus,alpha-conotoxinMIappearstointeractwiththeportionofthebindingsiteresponsibleforstABIlizingagonistcationsbutdoesnotdosowithacationicresidueandis,consequently,incapableofinducingaconformationalchange.

PapineniRV., etal. (2001) Site-specificchargeinteractionsofalpha-conotoxinMIwiththenicotinicacetylcholinereceptor. JBiolChem. PMID:11323431

品牌介绍
Smartox Biotechnology 是全球唯一一家专门生产动物毒液多肽毒素,用于细胞离子通道功能研究的生物医药公司。多肽毒素在生物制药领域具有重要的使用价值。Smartox Biotechnology 于 2009 年由来自 Grenoble 神经科学研究所 (Grenoble Institute of Neuroscience) 的 Michel de waard 博士创立, Smartox Biotechnology 专门研究动物毒液,制作合成多种毒液中的多肽成分(常称为毒素)。 De Waard 博士研究离子通道与毒素多肽的关系,尤其是鉴定、开发毒素多肽作为治疗性分子或细胞穿透肽 (cell penetrating peptides, CPP) 。其研究团队在毒液分离,药理性活性肽鉴定、富半胱氨酸肽定性、制作和优化等方面具有独特、丰富的经验。 2010 年, Smartox Biotechnolgy 被法国研究部 (Ministry of Research) 授予“新兴企业 OSEO 奖 (OSEO prize for emerging businesses) ”。