Obtustatin isa41aminoaciddisintegrinpeptideisolatedfromthevenomoftheViperalebetinaobtusa.Itisapotent(IC50 =2nM)and selectiveinhibitorofthebindingofα1β1 integrintocollagenIV.Contrarytootherknowndisintegrins,itdoesnotcontaintheclassicalRGDsequence. Obtustatin doesnotshowinhibitoryactivitytowardotherintegrins,includingα2β1,αIIbβ3,αvβ3,α4β1,α5β1,α6β1,andα9β1,α4β7 integrins. Obtustatin potentlyinhibitsangiogenesisinchickenandinmousemodelandreducestumordevelopmentbyhalf.Description:Productcode:10OBT001.Category:Integrins.Tag:integrin.AAsequence: Cys1-Thr-Thr-Gly-Pro-Cys6-Cys7-Arg-Gln-Cys10-Lys-Leu-Lys-Pro-Ala-Gly-Thr-Thr-Cys19-Trp-Lys-Thr-Ser-Leu-Thr-Ser-His-Tyr-Cys29-Thr-Gly-Lys-Ser-Cys34-Asp-Cys36-Pro-Leu-Tyr-Pro-Gly-OHDisulfidebonds: Cys1-Cys10,Cys6-Cys29,Cys7-Cys34 andCys19-Cys36Length(aa): 41Formula: C184H284N52O57S8MolecularWeight: 4393.13 DaAppearance:WhitelyophilizedsolidSolubility: aqueousbufferCASnumber: notavailableSource: SyntheticPurityrate: >97%Reference:StructuralanddynamicalpropertiesofKTS-disintegrins:AcomparisonbetweenObtustatinandLebestatinObtustatinandLebestatinarelysine-threonine-serine(KTS)-disintegrins,whichareafamilyoflowmolecularweightpolypeptidespresentinmanyviperidaevenomsandarepotentandspecificinhibitorsofcollagen-bindingintegrins.Theintegrinbindingloop,harboringthe(21)KTS(23)motif,andtheC-terminaltailareknowntoberesponsIBLefortheselectivebindingtotheα1β1integrin.Despiteaveryhighsequencehomology(onlytwomutationsarepresentinLebestatinrelativetoObtustatin,namelyR24LandS38L),LebestatinexhibitsahigherinhibitoryeffectthanObtustatinoncelladhesionandcellmigrationtocollagensIandIV.Hereweshow,bymeansofmoleculardynamicssimulationsofthetwopolypeptidesinaqueoussolution,thatLebestatinpossessesahigherflexibilityoftheC-terminaltailandagreatersolventaccessibilityoftheintegrinbindingloopthanObtustatin.Itmaybehypothesizedthatthesepropertiesmaycontributetothehigherbinding-affinityofLebestatintoitsBIOLOGicalpartner.©2012WileyPeriodicals,Inc.DaidoneI, etal. (2013)StructuralanddynamicalpropertiesofKTS-disintegrins:AcomparisonbetweenObtustatinandLebestatin. Biopolymers. PMID: 23097229Angiostaticactivityofobtustatinasalpha1beta1integrininhibitorinexperimentalmelanomagrowthThepresentedresultsshowtheeffectoftargetingofcollagenreceptor,alpha1beta1integrinexpressedontheendothelialcellsonthedevelopmentofexperimentalmelanomaandpathologicalangiogenesis.Obtustatin,asnakevenomKTS-disintegrin,wasappliedasaspecificinhibitorofthisintegrin.Thislowmolecularweightpeptiderevealedapotenttherapeuticeffectonmelanomaprogressionin2animalsystems,mouseandquail.Itsoncostaticeffectwasrelatedtotheinhibitionofangiogenesis.ObtustatininhibitedtheneovascularizationratioontheCAMembryoofquail,whichwaspathologicallyinducedbythedevelopingtumor.Thei.v.admiNISTrationofobtustatincompletelyblockedcancergrowthofMV3humanmelanomainnudemice.InB16F10syngeneicmousemodeltreatmentwiththedisintegrinrevealedalowereffect,althoughthedevelopmentofthetumorwassignificantlyreducedforbothdosages.Themechanismofobtustatinactionisrelatedtotheblockingofmicrovascularendothelialcellproliferation,whichundergoesapoptosisincaspase-dependentmanner.Summarizing,wepresentstudiesoflowmolecularweightdisintegrin,obtustatinasapotentialtherapeuticcompoundfortreatmentofmelanomathatcontainahighlevelofvascularization.BrownMC, etal. (2008)Angiostaticactivityofobtustatinasalpha1beta1integrininhibitorinexperimentalmelanomagrowth.IntJCancer. PMID: 18712720KTSandRTS-disintegrins:anti-angiogenicvipervenompeptidesspecificallytargetingthealpha1beta1integrinIntegrinsalpha(1)beta(1)andalpha(2)beta(1)arehighlyexpressedonthemicrovascularendothelialcells,andblockingoftheiradhesivepropertiessignificantlyreducedtheVEGF-drivenneovascularizationratioandtumorgrowthinanimalmodels.Hence,inhibitorsofthealpha(1)beta(1)andalpha(2)beta(1)integrins,aloneorincombinationwithantagonistsofotherintegrinsinvolvedinangiogenesis(eg.alpha(v)beta(3),alpha(v)beta(5),andalpha(6)beta(4)),mayprovebeneficialinthecontroloftumorneovascularization.Viperidaesnakeshavedevelopedintheirvenomsanefficientarsenalofintegrinreceptorantagonists.KTS-(obtustatin,viperistatin,lebestatin)andRTS-(jerdostatin)disintegrinsrepresentvipervenompeptidesthatspecificallyblocktheinteractionofthealpha(1)beta(1)integrinwithcollagensIVandIinvitroandangiogenesisinvivo.Thepossibletherapeuticapproachtowardstumorneovascularizationbytargetingthealpha(5)beta(1),alpha(v)beta(5)andalpha(v)beta(3)integrinswithRGD-bearingdisintegrinshasbeenexploredinanumberoflaboratories.Herewediscussstructure-functioncorrelationsofthenovelgroupofspecific(K/R)TS-disintegrinstargetingthealpha(1)beta(1)integrin.CalveteJJ, etal. (2007)KTSandRTS-disintegrins:anti-angiogenicvipervenompeptidesspecificallytargetingthealpha1beta1integrin. CurrPharmDes. PMID: 17979730Aminoacidsequenceandhomologymodelingofobtustatin,anovelnon-RGD-containingshortdisintegrinisolatedfromthevenomofViperalebetinaobtusaDisintegrinsrepresentagroupofcysteine-richpeptidesoccurringinCrotalidaeandViperidaesnakevenoms,andarepotentantagonistsofseveralintegrinreceptors.Anoveldisintegrin,obtustatin,wasisolatedfromthevenomoftheViperalebetinaobtusaviper,andrepresentsthefirstpotentandselectiveinhibitorofthebindingofintegrinalpha(1)beta(1)tocollagenIV.Theprimarystructureofobtustatincontains41aminoacidsandistheshortestdisintegrindescribedtodate.Obtustatinsharesthepatternofcysteinesofothershortdisintegrins.However,incontrasttoknownshortdisintegrins,theintegrin-bindingloopofobtustatinistworesiduesshorteranddoesnotexpresstheclassicalRGDsequence.Usingsyntheticpeptides,aKTSmotifwasidentifiedastheintegrin-bindingsequence.Athree-dimensionalmodelofobtustatin,builtbyhomology-modelingstructurecalculationsusingdifferenttemplatesandalignments,stronglyindicatesthatthenovelKTSmotifmayresideatthetipofaflexibleloop.Moreno-MurcianoM.P., etal.(2003)Aminoacidsequenceandhomologymodelingofobtustatin,anovelnon-RGD-containingshortdisintegrinisolatedfromthevenomofViperalebetinaobtusa. ProteinSci. PMID: 12538900Obtustatin:apotentselectiveinhibitorofalpha1beta1integrininvitroandangiogenesisinvivoAnoveldisintegrin,obtustatin,waspurifiedfromthevenomoftheViperalebetinaobtusaviper.Obtustatinistheshortestdisintegrinyetdescribed,containingonly41aminoacids.ItcontainsasimilarpatternofcysteinestotheshortdisintegrinsechistatinanderistostatinbutcontainsthesequenceKTSratherthanRGDinitsactivesiteloop.Obtustatinisapotentandselectiveinhibitorofalpha1beta1integrin.Itdoesnotinhibitthecloselyrelatedintegrinalpha2beta1,norapanelofotherintegrinstested.Itdoesnotinhibitligandbindingtotherecombinantalpha1I-domain.Importantly,obtustatinpotentlyinhibitedangiogenesisinvivointhechickenchorioallantoicmembraneassay,andintheLewislungsyngeneicmousemodel,itreducedtumordevelopmentbyhalf,confirmingandextendingpreviousresultsontherelevanceofalpha1beta1integrintoangiogenesisandsuggestingnovelapproachestothegenerationofangiogenesisinhibitors.MarcinkiewiczC., etal.(2003)Obtustatin:apotentselectiveinhibitorofalpha1beta1integrininvitroandangiogenesisinvivo. CancerRes. PMID: 12727812NMRsolutionstructureofthenon-RGDdisintegrinobtustatinThesolutionstructureofobtustatin,anovelnon-RGDdisintegrinof41residuesisolatedfromViperalebetinaobtusavenom,andapotentandselectiveinhibitoroftheadhesionofintegrinalpha(1)beta(1)tocollagenIV,hasbeendeterminedbytwo-dimensionalnuclearmagneticresonance.Almostthewholesetofchemicalshiftsfor1H,13Cand15Nwereassignedatnaturalabundancefrom2Dhomonuclearandheteronuclear500MHz,600MHzand800MHzspectraatpH3.0recordedat298Kand303K.Finalstructuralconstraintsconsistedof302non-redundantNOE(95long-range,60medium,91sequentialand56intra-residue),fourdisulfidebonddistances,fivechi1dihedralanglesandfourhydrogenbonds.The20conformerswithlowesttotalenergyhadnoNOEviolationsgreaterthan0.35Aordihedralangleviolationsgreaterthan12degrees.Theaverageroot-mean-squaredeviation(RMSD)forbackboneatomsofallresiduesamongthe20conformerswas1.1Aand0.6Aforthe29best-definedresidues.Obtustatinlacksanysecondarystructure.ComparedtoallknowndisintegrinstructuresinwhichtheRGDmotifislocatedattheapexofan11residuehairpinloop,theactiveKTStripeptideofobtustatinisorientedtowardsasideofitsnineresidueintegrin-bindingloop.TheC-terminaltailisneartotheactiveloop,andthesetwostructuralelementsdisplaythelargestatomicdisplacementsduetolocalconformationaldisorder.Doublecross-peaksforW20,Y28andH27inthearomaticregionofTOCSYspectra,localRMSDvaluesfortheseresidues,andpositivecross-peaksinaROESYspectrum(600MHz,100msmixingtime),suggestthattheseresiduesactasahingeallowingfortheoverallflexibilityoftheentireintegrin-bindingloop.Thesedistinctstructuralfeatures,alongwithitsdifferentelectrostaticsurfacepotentialinrelationtootherknowndisintegrins,mayconfertoobtustatinitsreportedalpha(1)beta(1)integrininhibitoryselectivity.Moreno-MurcianoM.P., etal.(2003)NMRsolutionstructureofthenon-RGDdisintegrinobtustatin. J.Mol.Biol. PMID: 12742023