简介:Inthepost-genomicera,variouscomputationalmethodsthatpredictprotein-proteininteractionsatthegenomelevelareavailable;however,eachmethodhasitsownadvantagesanddisadvantages,resultinginfalsepredictions.Herewedevel-opedauniqueintegratedapproachtoidentifyinteractingpartner(s)ofSemaphorin5A(SEMA5A),beginningwithsevenproteinssharingsimilarligandinteractingresiduesasputativebindingpartners.ThemethodsincludeDwyerandRoot-Bernstein/Dillontheoriesofproteinevolution,hydropathiccomplementarityofproteinstructure,patternofproteinfunctionsamongmolecules,informationondomain-domaininteractions,co-expressionofgenesandproteinevolution.AmongthesetofsevenproteinsselectedasputativeSEMA5Ainteractingpartners,wefoundthefunctionsofPlexinB3andNeuropilin-2tobeassociatedwithSEMA5A.WemodeledthesemaphorindomainstructureofPlexinB3andfoundthatitsharessimilaritywithSEMA5A.Moreover,avirtualexpressiondatabasesearchandRT-PCRanalysisshowedco-expressionofSEMA5AandPlexinB3andtheseproteinswerefoundtohaveco-evolved.Inaddition,weconfirmedtheinterac-tionofSEMA5AwithPlexinB3inco-immunoprecipitationstudies.Overall,thesestudiesdemonstratethatanintegratedmethodofpredictioncanbeusedatthegenomelevelfordiscoveringmanyunknownproteinbindingpartnerswithknownligandbindingdomains.
简介:TheE(envelope)proteinisthesmalleststructuralproteininallcoronavirusesandistheonlyviralstructuralproteininwhichnovariationhasbeendetected.WeconductedgenomesequencingandphylogeneticanalysesofSARS-CoV.Basedongenomesequencing,wepredictedtheEproteinisatransmembrane(TM)pro-teincharacterizedbyaTMregionwithstronghydrophobicityandα-helixcon-formation.Weidentifiedasegment(NH2-_L-Cys-A-Y-Cys-Cys-N_-COOH)inthecarboxyl-terminalregionoftheEproteinthatappearstoformthreedisulfidebondswithanothersegmentofcorrespondingcysteinesinthecarboxyl-terminusoftheS(spike)protein.ThesebondspointtoapossiblestructuralassociationbetweentheEandSproteins.OurphylogeneticanalysesoftheEproteinsequencesinallpub-lishedcoronavirusesplaceSARS-CoVinanindependentgroupinCoronaviridaeandsuggestanon-humananimalorigin.