简介:Theaimofthisstudyistoexpressthereceptor-bindingdomainofBacillusanthracisprotectiveantigeninE.coli.SignalsequenceoftheoutermembraneproteinA(OmpA)ofE.coliwasattachedtothe5'endofthegeneencodingprotectiveantigenreceptor-bindingdomain(the4^thdomainofPA,PALM).TheplasmidcarryingthefusiongenewasthentransformedintoE.coliandinducedtoexpressrecombinantPAlMbyIFFG.TherecombinantproteinwaspurifiedbychromatographyandthenidentifiedbyN-terrainalsequencingandWesternblot.Therecombinantprotein,about10%ofthetotalbacterialproteininvolume,wassecretedtotheperiplasmicspaceofthecell.Afterapurificationprocedureincludingionexchangechromatographyandgelfiltration,about10mgofhomogenousrecombinantPAD4wasobtainedfrom1Lculture.DatafromN-terminalsequencingsuggestedthattheaminoacidsequenceofrecombinantPAD4wasidenticalwithitsnaturalcounterpart.AndtheresultofWesternblotshowedtherecombinantproteincouldbindwithanti-PAserumfromrabbit.HighlevelsecretedexpressionofPAD4wasobtainedinE.coli.TheresultsreportedherearepartsofacontinuingresearchtoevaluatePAD4asapotentialdrugforanthraxtherapyoracandidateofnewvaccine.