Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Chemistry 501 Handout 8 Nucleotides and Nucleic AcidsChapter 8Dep. of Chemistry & BiochemistryProf. IndigLehninger. Principles of Biochemistry.by Nelson and Cox, 5th Edition; W.H. Freeman and CompanyStructure of nucleotidesMajor purine and pyrimidine bases of nucleic acidsConformation of riboseopposite side of the planerelative to the C-5’ atomsame side of the planerelative to the C-5’ atomRibonucleotides of nucleic acidsDeoxyribonucleotides of nucleic acidsSome minor purine and pyrimidine bases, shown as the nucleosidesMinor bases of DNA Minor bases of tRNAsSome adenosine monophosphatesHydrolysis of RNA under alkaline conditionsPhosphodiester bonds link successive nucleotides in nucleic acidsSome adenosine monophosphatesPhosphodiester linkages in the covalent backbone of DNA and RNASchematic representation of the nucleotide sequences of nucleic acidsThe properties of nucleotide bases affect the three-dimensional structure of nucleic acidsFree pyrimidine and purine bases may exist in two or more tautomeric forms depending on the pH.As a result of resonance, all nucleotide bases absorb UV light.Hydrogen-bonding patters in the base pairs defined by Watson and CrickWatson-Crick model for the structure of DNAX-ray diffraction pattern of DNAComplementarity of strands in the DNA double helixReplication of DNA as suggested by Watson and CrickDNA can occur in different three-dimensional formsStructural variations in DNAComparison of A, B, and Z forms of DNACertain DNA sequences adopt unusual structuresDNA structures containing three or four DNA strandsHoogsteen pairingMessenger RNAs code for polypeptide chainsMessenger RNA is only one of several classes of cellular RNAThe product of transcription of DNA is always single-stranded RNA.The single strand tends to assume a right-handedhelical conformation dominated by base-stackinginteractions.BasesP atomsRiboses and phosphate oxygensSecondary structure of RNAsBase-paired helical structuresin an RNANon Watson-Crick base pairsComplementary sequences thatmay be paired in the 3D structureThree-dimensional structure in RNAPhenylalanine tRNA of yeastA hammerhead ribozyme from a plant virusAn intron (segment of mRNA) from the ciliated protozoan Tetrahymena thermophilaSome unusual base-pairing patters found in this tRNADouble-helical DNA and RNA can be denaturedReversible denaturation and annealing (renaturation) of DNAHeat denaturation of DNAPartially denatured DNABubblesRegions rich in A=T base pairs specifically denature, while most DNAremains double-strandedDNA hybridizationNucleic acids from different species can form hybridsCan be used to detect similar DNAsequences in two different species or within the genome of a single speciesNucleotides and nucleic acids undergo nonenzymatic transformations100 per day per cellIn DNA, uracil residues are removed by the repair system 1 per day per cell10,000 per day per cellFormation of pyrimidine dimers induced by UV lightAlkylating agents can alter certain bases of DNACannot base-pair with cytosineChemical agents that cause DNA damageDeaminatingagentsThe sequences of long DNA strands can be determinedDNA sequencing by the Sanger methodStrategy for automating DNA sequencing reactionsThe chemical synthesis of DNA has been automateddimethoxytritylOther functions of nucleotidesNucleotides carry chemical energy in cells.Adenine nucleotides are components of many enzyme cofactors.Some nucleotides are regulatory molecules.Nucleoside phosphatesThe phosphate ester and phosphoanhydride bonds of ATPSome coenzymes containing adenosineThree regulatory