第21和第22种氨基酸---化学通报

(730000#730030)2122──UGAUAG20UAGUGAThe21stand22ndAminoAcidQiuWenyuan,DengWenye,CaiYanqiao,#YanRuiqing(DepartmentofChemistry,StateKeyLaboratoryofAppliedOrganicChemistry,LanzhouUniversity,Lanzhou730000)(#LanzhouMaternityandChildHealthHospital,Lanzhou730030)AbstractThisarticleintroducestheundiscoveredtwoaminoacids──the21staminoacidandthe22ndaminoacid,whicharecalledselenocysteineandpyrrolysine,respectively.Theyarenonstandardaminoacidsanddirectlyencodedbygeneticcodes.TheirRNAnucleotidetripletsareUGAandUAG,respectively.Theencodingwayofthesetwoaminoacids,whicharedifferentfromthosetwentystandardaminoacids,leadtotheproblemofcodonredefinition.KeywordsAminoacid,Selenocysteine,Pyrrolysine,UAGcodon,UGAcodon4(U,C,G,A)(RNA)20(20)(43=64)[1]AUG()UAAUGAUAG1986Chamber[2]Zinoni[3](Selenocysteine)2120025Srinivasan[4]Hao[5]22──(Pyrrolysine)(UGA)(UAG)(UAA,UGA,UAG)[6]12147E-mail:[e-mail](2017302390203012)(20020730006)2002-07-102003-01-14[2]()(GSHPx)UGAZinoni[3]UGA(FDHH)fdhF715fdhF140(UGA)129268β-UAAUGASel(SelcSelASelB)Selc95tRNAUCA8DD5(G9G12U15C16C25)tRNAUCAL--tRNAUCASelASelBUGAmRNASeS+4+6DNACu/Zn()UGA(1)-SH-SeH/H2NCHCCH2OHOSeHH2NCHCCH2OHOSH(Cys)(Sec)1Fig.1Molecularstructuresforthecysteineandselenocysteine22222Krzycki[4,5](MtmBDtmBTtmB)(UAG)UAG(4R,5R)-4---5-pyl(pylTpylS)pylTtRNACUA6534D21pylS(LysRS)tRNACUA-tRNACUApylTpylBpylC-tRNACUA-tRNACUA-tRNACUA90º(2)(3)UAG2L-(AC)Fig.2TheStick-diagramsoftoworientations(AandC)ofL-pyrrolysineaminoacidCH2CHCOOHNH24(Lys)NCRNHOCH2CHCOOHNH2OH)NH2,CH3,(R:4(Pyl)H2N3Fig.3Molecularstructuresforthelysineandpyrrolysine(MtmC,MtmC(MtmB)C-2MtmB(DMA)(TMA)UAG4Gln259C-2Gln259Gln333C-2MtmCNHOOHOOOH2NHONHOOHOOOH2NONHHCH3HHOOOONOH2NHONHHCH3HHOOOONOH2NHONHHCH3HHOOOONOH2NHONHHCH3HHOOOONOH2NHONHHHHNH3E229E259+CH3NH2E229E259E229E259++E229E259+CoE229E259CoE229E259++H+ABCDEFXXXXXXQ333Y335Q333Y335Q333Y335Q333Y335Q333Y335Q333Y3354MtmBMtmCFig.4AmechanismforhowMtmBassistsinthetransferofthemethylgroupofmonomethylaminetothecorrionoidcofactorofMtmC(UAG)(UAG)2220UGA21──UAG22──(1)(2)tRNA(3)tRNAUAAUGAUAG3UGAUAG(UAA)1[1]DRHofstadter.Sci.Amer.,1982,246(3):18~29.[2]IChambers,JFrampton,PGoldfarbetal.EMBOJ.,1986,5:1221~1227.[3]FZinoni,ABirkmann,TCStadtmanetal.Proc.Natl.Acad.Sci.U.S.A.,1986,83:4650~4654.[4]GSrinivasan,CMJames,JAKrzycki.Science,2002,296:1459~1462.[5]BHao,WGong,TKFergusonetal.Science,2002,296:1462~1466.[6]JFAtkins,RGesteland.Science,2002,296:1409~1410.