RecAisessentialforhomologousrecombination,reactionsinvolvingDNArepairandUV-inducedmutagenesisinEcoli(1,2,3).RecAbindstosinglestrandedDNA,resultinginthepolymerizationofRecAintoanucleoproteincomplex.ThiscomplexcanalignwithcomplementarydoublestrandedDNA,resultinginRecAcatalysisofDNAstrandexchange.RecADNAbindingisstimulatedbyATPhydrolysisornon-hydrolyzableATPanalogs.TheRecA-ATP-singlestrandedDNAcomplexalsocanfunctionasacoproteaseintheproteolyticcleavageofLexA,UmuDandcertainbacteriophageproteins.Inahealthycell,LexArepressestheexpressionofgenesencodingDNArepairproteins(SOSgenes).UponinjuryofDNA,LexAcatalyzesitsowndigestion,therebyallowingsynthesisofnecessarySOSproteins.However,LexAcanonlyinduceself-catalysiswhenactivatedbyassDNA-RecAfilament.AsinglefilamentwillbindandactivateseveralLexAproteins,eachofwhichthencleavesotherboundproteins.Thus,ssDNA-RecA,aproductofDNAinjury,stimulatesDNArepair.

• VisualizationofDNAstructureswithelectronmicroscopy(3)
• D-loopmutagenesis(4)
• ScreeninglibrariesusingRecA-coatedprobes(5,6)
• CleavageofDNAatanysinglepredeterminedsite(7,8,9)
• RecAmediatedaffinitycaptureforfulllengthCDNAcloning(10,11)

RecA:2mg/mlin10mMTris-HCl,1mMDTT,0.1mMEDTA,50%glycerol,pH7.5@25°C

Theabsenceofexo-andendodeoxyribonucleases,non-specificDNaseandRNaseisconfirmedbyappropriatequalitytest.

-20°C

1. West,S.C.(1992).Ann.Rev.Biochem..61,603-640.
2. Radding,C.M.(1991).J.Biol.Chem..266,5355-5358.
3. Wasserman,S.A.andCozzarelli,N.R.(1985).Proc.Natl.Acad.Sci.USA.82,1079-1083.
4. Shortle,D.etal.(1980).Proc.Natl.Acad.Sci.USA.77,5375-5379.
5. Honigberg,S.M.etal.(1986).Proc.Natl.Acad.Sci.USA.83,9586-9590.
6. Rigas,B.etal.(1986).Proc.Natl.Acad.Sci.USA.83,9591-9595.
7. Ferrin,L.J.andCamerini-Otero,R.D.(1991).Science.254,1494-1497.
8. Koob,M.etal.(1992).Nucl.AcidsRes..20,5831-5836.
9. Koob,M.(1992).R.Wu(Ed.),MethodsinEnzymology.216,321-329.SanDiego:AcademicPress.
10. Zhumabayeva,B.etal.(1990).Biotechniques.27,834-845.
11. Zhumabayeva,B.etal.(2001).Biotechniques.30,512-520.