Scyllatoxin(Leiurotoxin-1)isaneurotoxinthatwasoriginallyisolatedfromLeiurusquinquestriatushebraeus.ScyllatoxinbindsandblocksSKchannels(smallconductanceCa2+-activatedK+channels)inthebrainandspinalcordandinhibitsthem.
AAsequence:Ala-Phe-Cys3-Asn-Leu-Arg-Met-Cys8-Gln-Leu-Ser-Cys12-Arg-Ser-Leu-Gly-Leu-Leu-Gly-Lys-Cys21-Ile-Gly-Asp-Lys-Cys26-Glu-Cys28-Val-Lys-His-NH2
Disulfidebondsbetween:Cys3-Cys21,Cys8-Cys26andCys12-Cys28
Length(aa):31
Formula:C142H237N45O39S7
MolecularWeight:3424.1Da
Appearance:Whitelyophilizedsolid
Solubility:waterandsalinebuffer
CASnumber:[116235-63-3]Source:Synthetic
Purityrate:>95%
TheeffectsofcharybdotoxinandleiurotoxinIwereexaminedonseveralclassesofK+currentsinbullfrogsympatheticganglionandhippocampalCA1pyramidalneurons.Highlypurifiedpreparationsofcharybdotoxinselectivelyblockedalargevoltage-andCa(2+)-dependentK+current(IC)responsIBLeforactionpotentialrepolarization(IC50=6nM)whileleiurotoxinIselectivelyblockedasmallCa(2+)-dependentK+conductance(IAHP)responsiblefortheslowafterhyperpolarizationfollowinganactionpotential(IC50=7.5nM)inbullfrogsympatheticganglionneurons.NeitherofthetoxinshadsignificanteffectsonotherK+currents(M-current[IM],A-current[IA]andthedelayedrectifier[IK])presentinthesecells.LeiurotoxinIataconcentrationof20nMhadnodetectableeffectoncurrentsinhippocampalCA1pyramidalneurons.ThislackofeffectonIAHPincentralneuronssuggeststhatthechannelsunderlyingslowAHPsinthoseneuronsarepharmacologicallydistinctfromanalogouschannelsinperipheralneurons.
GohJW.,etal.(1992)EffectofcharybdotoxinandleiurotoxinIonpotassiumcurrentsinbullfrogsympatheticganglionandhippocampalneurons.BrainRes.PMID: 1280181
WehaveisolatedanhSK3isoformfromahumanembryonicCDNAlibrarythatwehavenamedhSK3_ex4.Thisisoformcontainsa15aminoacidinsertionwithintheS5toP-loopsegment.TranscriptsencodinghSK3_ex4arecoexpressedatlowerlevelswithhSK3inneuronalaswellasinnon-neuronaltissues.ToinvestigatethepharmacokineticpropertiesofhSK3_ex4,weexpressedtheisoformshSK3andhSK3_ex4intsAcells.BothisoformsweresimilarlyactivatedbycytosolicCa2+(hSK3,EC50=0.91+/-0.4microM;hSK3_ex4,EC50=0.78+/-0.2microM)andby1-ethyl-2-benzimidazolinone(hSK3,EC50=0.17mM;hSK3_ex4,0.19mM).Theywerebothblockedbytetraethylammonium(hSK3,Kd=2.2mM;hSK3_ex4,2.6mM)andshowedsimilarpermeABIlitiesrelativetoK+forCs+(hSK3,0.17+/-0.04,n=3;hSK3_ex4,0.17+/-0.05,n=3)andRb+(hSK3,0.79+/-0.04,n=3;hSK3_ex4,0.8+/-0.07,n=3).Ba2+blockedbothisoforms,andinbothcases,theblockwasstrongestathyperpolarizingmembranepotentials.However,thevoltage-dependenceofhSK3wasstrongerthanthatofhSK3_ex4.ThemostobviousdistinguishingfeatureofthisnewisoformwasthatwhereashSK3wasblockedbyapamin(Kd=0.8nM),scyllatoxin(Kd=2.1nM),andd-tubocurarine(Kd=33.4microM),hSK3_ex4wasnotaffectedbyapaminupto100nM,scyllatoxinupto500nM,andd-tubocurarineupto500microM.Sofar,isoformhSK3_ex4formstheonlysmall-conductancecalcium-activatedpotassium(SK)channels,whichareinsensitivetotheclassicSKblockers.
WittekindtOH.,etal.(2004)Anapamin-andscyllatoxin-insensitiveisoformofthehumanSK3channel.MolPharmacol.PMID: 14978258
Recently,wereportedastructure-activityrelationshipstudyonP05,anovelleiurotoxinI-likescorpiontoxinwhichisselectivefortheapamin-sensitiveCa(2+)-activatedK+channel[Sabatieretal.(1993)Biochemistry32,2763-2770].Arg6,Arg7andC-terminalHis31appearedtobekeyresiduesforP05BIOLOGicalactivity.OwingtothehighsequenceidentitybetweenP05andleiurotoxinI(87%),severalanalogsofleiurotoxinI(Lei-NH2)withpointmutationsatthesepositionsweredesignedandchemicallysynthesizedusinganoptimizedsolid-phasetechnique.Thesynthesizedpeptideswere[L6]Lei-NH2,[R7]Lei-NH2,Lei-OHand[R7]Lei-OH,aswellasfragment[R7,Abu8]N4-S11-NH2.Achimericanalog([M22,K24,R27]Lei-NH2),whichpossessespartoftheiberiotoxinC-terminus,wasalsoconstructed.Circulardichroismanalysesoftheseanalogs,inagreementwiththeirstructuralmodelsobtainedbymoleculardynamics,showedthatthepointmutationsdidnotsignificantlyaffecttheoverallsecondarystructures,ascomparedtonaturalLei-NH2.Allthepeptidesandnaturaltoxinswerecomparedinvitrofortheircapacitytoinhibitbindingof[125I]-apamintoratbrainsynaptosomes,andinvivofortheirspecificneurotoxicityinmice.TheArg6residuewasessentialforhighbiologicalactivityofleiurotoxinI.Further,substitutionofMet7inthenaturaltoxinbyArg7,orC-terminalamidationofHis31,greatlyincreasedaffinityfortheapaminreceptorbutdidnotsignificantlyaffecttoxinneurotoxicity.Remarkably,thechimericanalog[M22,K24,R27]Lei-NH2wasfoundtoretainleiurotoxinI-likeactivity,thusindicatingthatthenegativelychargedresiduesAsp24andGlu27(andIle22)arenotdirectlyinvolvedinthehightoxinbioactivity.However,thechimericmoleculehadnoiberiotoxin-likeeffectonratmuscularmaxi-K+channelsincorporatedinlipidbilayers.
SabatierJM.,etal.(1994)LeiurotoxinI,ascorpiontoxinspecificforCa(2+)-activatedK+channels.Structure-activityanalysisusingsyntheticanalogs.IntJPeptProteinRes. PMID: 8070973
Chemicalmodificationsofscyllatoxin(leiurustoxinI)haveshownthattwoargininesinthesequence,Arg6andArg13,areessentialbothforbindingtotheCa(2+)-activatedK+channelproteinandforthefunctionaleffectofthetoxin.His31isimportantbothforthebindingactivityofthetoxinandfortheinductionofcontractionsontaeniacoli.However,althoughitsiodinationdrasticallydecreasesthetoxinactivity,itdoesnotabolishit.ChemicalmodificationoflysineresiduesorofGlu27doesnotsignificantlyaltertoxinbinding,butitdrasticallydecreasespotencywithrespecttocontractionoftaeniacoli.Thesameobservationhasbeenmadeafterchemicalmodificationofthelysineresidues.ThebraindistributionofscyllatoxinbindingsiteshasbeenanalyzedbyquantitativeautorADIographicanalysis.Itindicatesthatapamin(abeevenomtoxin)bindingsitesarecolocalizedwithscyllatoxinbindingsites.Theresultsareconsonantwiththepresenceofapamin/scyllatoxinbindingsitesassociatedwithCa(2+)-activatedK+channels.High-affinitybindingsitesforapamincanbeassociatedwithvery-high-affinity(lessthan70pM),high-affinity(approximately100-500pM),ormoderate-affinity(greaterthan800pM)bindingsitesforscyllatoxin.
AugusteP.,etal.(1992)Scyllatoxin,ablockerofCa(2+)-activatedK+channels:structure-functionrelationshipsandbrainlocalizationofthebindingsites.Biochemistry. PMID: 1731919
Aninhibitorofapaminbindinghasbeenpurifiedtohomogeneityinthreechromatographicstepsfromthevenomofthescorpion,Leiurusquinquestriatushebraeus.Theinhibitor,whichwehavenamedleiurotoxinI,representslessthan0.02%ofthevenomprotein.Itisa3.4-kDapeptidewithlittlestructuralhomologytoapaminalthoughithassomehomologytootherscorpiontoxinssuchascharybdotoxin,noxiustoxin,andneurotoxinP2.LeiurotoxinIcompletelyinhibits125I-apaminbindingtoratbrainsynaptosomalmembranes(Ki=75pM).Thus,itis10-20-foldlesspotentthanapamin.LeiurotoxinIisnotastrictlycompetitiveinhibitorofthisbindingreaction.Likeapamin,leiurotoxinIblockstheepinephrine-inducedrelaxationofguineapigteniaecoli(ED50=6.5nM),whilehavingnoeffectontherateorforceofcontractioninguineapigatriaorrabbitportalveinpreparations.Thus,leiurotoxinIofscorpionvenomandapaminofhoneybeevenomdemonstratesimilaractivitiesinavarietyoftissues,yetarestructurallyunrelatedpeptides.Thesetwopeptidesshouldbeusefulinelucidatingtheroleofthesmallconductance,Ca2+-activatedK+channelsindifferenttissues.
ChicchiGG.,etal.(1988)Purificationandcharacterizationofaunique,potentinhibitorofapaminbindingfromLeiurusquinquestriatushebraeusvenom. PMID: 2839478
Purkinjecellshavespecializedintrinsicionicconductancesthatgeneratehigh-frequencyactionpotentials.DisruptionsoftheirCaorCa-activatedK(KCa)currentscorrelatewithalteredfiringpatternsinvitroandimpairedmotorbehaviorinvivo.ToexaminethepropertiesofsomaticKCacurrents,werecordedvoltage-clampedKCacurrentsinPurkinjecellbodiesisolatedfrompostnatalday17-21mousecerebellum.CurrentswereevokedbyendogenousCainfluxwithapproximatelyphysiologicalCabuffering.Purkinjesomataexpressedvoltage-activated,Cd-sensitiveKCacurrentswithiberiotoxin(IBTX)-sensitive(>100nS)andIBTX-insensitive(>75nS)components.IBTX-sensitivecurrentsactivatedandpartiallyinactivatedwithinmilliseconds.Rapid,incompletemacroscopicinactivationwasalsoevidentduring50-or100-Hztrainsof1-msdepolarizations.Incontrast,IBTX-insensitivecurrentsactivatedmoreslowlyanddidnotinactivate.Thesecurrentswereinsensitivetothesmall-andintermediate-conductanceKCachannelblockersapamin,scyllatoxin,UCL1684,bicucullinemethiodide,andTRAM-34,butwerelargelyblockedby1mMtetraethylammonium.Theunderlyingchannelshadsingle-channelconductancesof∼150pS,suggestingthatthecurrentsarecarriedbyIBTX-resistant(β4-containing)large-conductanceKCa(BK)channels.IBTX-insensitivecurrentswereneverthelessincreasedbysmall-conductanceKCachannelagoNISTsEBIO,chlorzoxazone,andCyPPA.Duringtrainsofbriefdepolarizations,IBTX-insensitivecurrentsflowedduringinterstepintervals,andtheaccumulationofinterstepoutwardcurrentwasenhancedbyEBIO.Incurrentclamp,EBIOslowedspiking,especiallyduringdepolarizingcurrentinjections.ThetwocomponentsofBKcurrentinPurkinjesomatalikelycontributedifferentlytospikerepolarizationandfiringrate.Moreover,augmentationofBKcurrentmaypartiallyunderlietheactionofEBIOandchlorzoxazonetoalleviatedisruptedPurkinjecellfiringassociatedwithgeneticataxias.
BentonMD.,etal.(2013)Iberiotoxin-sensitiveand-insensitiveBKcurrentsinPurkinjeneuronsomata.JNeurophysiol. PMID: 23446695
Smartox Biotechnolgy的多肽毒素产品如下:
1. 作用于钠离子通道(Sodium channel)的毒素
Toxin name | Catalog # | Target |
Phrixotoxin-3 | 13PHX003 | Selective blocker of Nav1.2 |
µ-conotoxin GIIIB | CON020 | Selective blocker of Nav1.4 |
µ-conotoxin CnIIIC | CON021 | Selective blocker of Nav1.4 |
μ-conotoxin PIIIA | 08CON006 | Selective blocker of Nav1.4 |
Jingzhaotoxin-III | 12JZH003 | Selective blocker of Nav1.5 |
ProTx-II | 07PTX002 | Selective blocker of Nav1.7 |
ProTx-II Biotin | 12PTB002 | Selective blocker of Nav1.7 |
ProTx-I | 12PTX001 | Blocker of Nav1.8, Nav1.2, Nav1.5, Nav1.7 |
Huwentoxin-I | 07HWT001 | Blocker of TTX-S |
Huwentoxin-IV | 08HWT002 | Blocker of TTX-S |
Hainantoxin-III | 13HTX003 | Blocker of TTX-S |
Hainantoxin-IV | 12HTX001 | Blocker of TTX-S |
GsAF-I | 12GSF001 | Blocker of TTX-S |
GsAF-II | 12GSF002 | Blocker of TTX-S |
2. 作用于钾离子通道(Potassium channel)的毒素
Toxin name | Catalog # | Target |
KCa channels | ||
Apamin 蜜蜂神经毒素 | 08APA001 | SK1, SK2, SK3 |
Charybdotoxin 蝎毒素 | 11CHA001 | KCa1.1, KCa3.1 - Kv1.2, Kv1.3, Kv1.6 |
Iberiotoxin | 12IBX001 | KCa1.1 |
Leiurotoxin 1 (Scyllatoxin) | 10LEI001 | SK1, SK2, SK3 |
Tamapin | 10TAM001 | SK1, SK2, SK3 |
Kaliotoxin-1 | 08KTX002 | BK, Kv1.1, Kv1.2, Kv1.3 |
Kv channels | ||
ShK | 08SHK001 | Kv1.3, Kv1.1, Kv1.4, Kv1.6 |
TMR-ShK | SAT001 | Kv1.3, Kv1.1 |
Margatoxin | 08MAG001 | Kv1.3 |
(Dap22)-ShK | 13SHD001 | Kv1.3 |
ADWX-1 | 13ADW001 | Kv1.3 |
HsTx1 | 08NEU001 | Kv1.3, Kv1.2 |
Agitoxin-2 | 13AGI002 | Kv1.3, Kv1.1 |
Maurotoxin | 08MAR001 | Kv1.2, KCa3.1 |
Guangxitoxin 1E | 11GUA002 | Kv2.1, Kv2.2 |
Stromatoxin 1 NEW | SCT01 | Kv2.1, Kv2.2 |
Kaliotoxin-1 | 08KTX002 | BK, Kv1.1, Kv1.2, Kv1.3 |
Charybdotoxin | 11CHA001 | KCa1.1, KCa3.1 - Kv1.2, Kv1.3, Kv1.6 |
Phrixotoxin-2 | PHX002 | Kv4.2, Kv4.3 |
AmmTx3 NEW | AMX001 | A-type potassium channels |
Inwardly rectifying potassium channels | ||
TertiapinQ | 08TER001 | Kir1.1, Kir3.1/3.4, Kir3.1/3.2-KCa1.1 |
hERG/Kv11.1 | ||
BeKm-1 | 13BEK001 | ERG1 |
3. 作用于钙离子通道(Calcium channel)的毒素
Toxin name | Catalog # | Target |
High voltage-gated Ca2+ channels | ||
ω-agatoxin IVA | 11AGA001 | P/Qtype |
ω-Conotoxin MVIIC | 08CON002 | P/Qtype, N-type |
ω-Conotoxin MVIIA | 08CON001 | N-type |
ω-Conotoxin GVIA | 08CON003 | N-type |
ω-Conotoxin SO3 | 08CON013 | N-type |
Huwentoxin I | 07HWT001 | N-type |
ProTx-II | 07PTX002 | T-type, L-type |
Intermediate voltage-gated Ca2+ channels | ||
SNX482 | 08SNX002 | R-type |
Low voltage-gated Ca2+ channels | ||
ProTx-I | 12PTX001 | T-type |
ProTx-II | 07PTX002 | T-type, L-type |
Ryanodine receptors | ||
Maurocalcine | 07PAU001 | Ryr1 |
4. 作用于氯离子通道(Chloride channel)的毒素
Toxin name | Catalog # | Target |
Chlorotoxin | 08CHL001 | Blocker of small conductance Cl- channels |
GaTx1 | 13GTX001 | Selective blocker of CFTR channel |
GaTx2 | 10GTX002 | Selective blocker of ClC-2 channel |
5. 作用于乙酰胆碱受体(Acetylcholine receptor)的毒素
Toxin name | Catalog # | Target |
α-conotoxin PeIA | 13CON017 | α9α10, α3β2 subunits |
α-Conotoxin PrXA | 13CON016 | α1/β1/ε/δ, α1/β1/γ/δ subunits |
Waglerin-1 | 12WAG001 | MusclenAChR |
α-conotoxin MI | 08CON012 | α1/δsubunits |
α-conotoxin GI | 08CON005 | α/δsite |
α-conotoxin IMI | 08CON011 | α7 homomeric nAChR |
α-conotoxin GID | CON019 | Blocker of α3β2, α7 and α4β2 nAChRs |
6. 含N-甲基-D-天冬氨酸NR2B
(NMDA, NR2B containing N-methyl-D-aspartate)
Conantokin-G
选择性、特异性抑制含NR2B的NMDAR。Conantokin-G能剂量依赖性抑制Ca2+内流,抑制NMDA诱导的兴奋性中毒效应。研究表明,在小鼠皮层神经元,Conantokin-G阻滞NMDA引发的电流信号的IC50值为480 nM。
7. 作用于酸敏感离子通道(ASIC channel, Acid-Sensing Ion Channel)的毒素
Toxin name | Catalog # | Target |
APETx2 | 07APE002 | Selective blocker of ASIC3 |
Psalmotoxin1/PcTx1 | 13PCT001 | Selective blocker of ASIC1a |
Ugr9-1 | 13UGR001 | Blocker of ASIC3 |
8. 作用于瞬时受体电位(TRP channel, transient receptor potential)的毒素
Toxin name | Catalog # | Target |
GsMTx4 | 08GSM001 | TRPC, TRPA |
Vanillotoxin3 | 10VAN003 | Activator of TRPV1 |
ProTx-I | 12PTX001 | Antagonist of TRPA1 |
9. 作用于嘌呤能通道(Purinergic channel)的毒素
Purotoxin-1
选择性抑制P2X3受体。100 nM Purotoxin-1 (PT-1)选择性抑制P2X3受体通道,在大鼠DRG神经元上,使用膜片钳实验表明:PT-1对电压门控通道和TRPV1均无抑制效应。10 µM ATP和100 µM α,β Methylene-ATP浓度下Purotoxin-1对P2X3受体有选择性作用,在该ATP浓度下Purotoxin-1对P2X2和杂化二聚体P2X2/3并无激动作用。Purotoxin-1对疼痛的潜在治疗作用。
10. 作用于其它膜受体通道(Others)的毒素
Smartox Biotechnology还提供其他类型的膜受体抑制剂:
Toxin name | Catalog # | Target |
Morphiceptin | 011CAS001 | Agonist of µ-opoid receptors |
Lys-conopressin G | 11CON14 | Vasopressin-like peptide |
GsMTx4 | 08GSM001 | Mechano sensitive ion channels |
Obtustatin | 10OBT001 | Blocks the binding of α1β1 integrin to collagen IV |
Rho-Conotoxin TIA | CON022 | Blocks α1-adrenergic receptor |
公司简介
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)”。
总之,Smartox Biotechnolgy提供一系列高质量、具开创价值的多肽毒素。这些化合物在离子通道 研究中具有高的亲和性和选择性,是相应领域科学研究理想的生物毒素提供商和贴心的合作伙伴。