生物化学 核苷酸和核酸.pptx

§8.1Nucleotides(核苷酸)§8.2NucleicAcids(核酸)§8.3NucleicAcidChemistry§8.4OtherFunctionsofNucleotides§8Nucleotidesnucleicacids1

b-RibonucleotideD-2

b-D-deoxyribonucleotide3

Basesinnucleotides4

§8.2NucleicAcidsBriefHistoryaboutDNADNAStructureRNAStructure5

1869,Miescherisolatesnuclein1928,GriffithfindsStreptococcustransformation1944,AverydiscoveredthatDNAwasthegeneticmaterialBy1947,ChargaffhaddevelopedaseriesofrulesbasedonasurveyofDNAcompositioninorganismsEarlyin1950s,WilkinsFranklinusedX-raycrystallographytostudythestructureofDNA1952,HersheyfarthershowedthatDNAwasthegeneticmaterial1953,WatsonCrickproposethedouble-helicalstructureofDNA......BriefHistoryaboutDNA6

1928,Griffith’stransformationexperiment(1)7

1928,Griffith’stransformationexperiment(2)8

1928,Griffith’stransformationexperiment(3)9

1928,Griffith’stransformationexperiment(4)Return10

1944,Avery-MacLeod-McCartyexperimentReturn11

Franklin’sX-raypictureforDNAReturn12

1952,AlfredD.HersheyMarthaChaseexperimentReturn13

Return14

DNAStructureDoubleHelix15

DNAStructure:doublehelix16

A-DNAB-DNAZ-DNAAllcontain21basepairsDNAStructure:threehelixforms(1)17

A-DNAB-DNAZ-DNADNAStructure:threehelixforms(2)B-DNA:生理条件下最稳定的构象；A-DNA:片段DNA在晶体状态下的构象，尚未知在细胞中是否存在；Z-DNA:生理条件下局部DNA可存在的构象，它表是该段DNA可能处于活动状态——转录、重组等.18

DNAStructure:Palindromesmirrorrepeats19

DNAStructure:Hairpin20

DNAStructure:Cruciform21

DNAStructure:threeDNAstrandsHoogsteenPairsWaston-CrickPairs22

DNAStructure:HDNA23

DNAStructure:fourDNAstrands(1)24

DNAStructure:fourDNAstrands(2)25

UnusualDNAstructures(includingtriplehelixandtetraplex)tendtoappearatsiteswhereimportanteventsinDNAmetabolism(replication,recombination,transcription)areinitiatedorregulated26

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§8.1Nucleotides(核苷酸)§8.2NucleicAcids(核酸)§8.3NucleicAcidChemistry§8.4OtherFunctionsofNucle