7 Macromolecules #3 Nuc Acids 9 14 05dstratto/bcor011_handouts/Vayda...Nucleic Acids Lecture 7...
Transcript of 7 Macromolecules #3 Nuc Acids 9 14 05dstratto/bcor011_handouts/Vayda...Nucleic Acids Lecture 7...
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9/14/05 BCOR 011
Nucleic Acids
Lecture 7Macromolecules #3
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Nucleic AcidsNucleic AcidsMonomer UnitsMonomer Units PolymersPolymers““Nucleotides”Nucleotides” ““PolynucleotidePolynucleotide
Chains”Chains”ribonucleotidesribonucleotidesATP GTP NADHATP GTP NADHCTPCTP UTP FADHUTP FADH22
ADP, AMP, ADP, AMP, cAMPcAMP, GDP, GDP
deoxydeoxyribonucleotidesribonucleotidesddATP ATP ddGTPGTPddCTP CTP (d)(d)TTPTTP
RNARNA
DNADNA
RRiboibo NNucleic ucleic AAcid cid
DDeoxyriboeoxyribo NNucleic ucleic AAcid cid
--Energy Carriers of the CellEnergy Carriers of the Cell--Building Blocks of RNABuilding Blocks of RNA
--Signaling and RegulatorySignaling and Regulatorymolecules of Processesmolecules of Processes
--Building Blocks of DNABuilding Blocks of DNAHugeHuge PolymerPolymer
Medium to Large PolymerMedium to Large Polymer--mmRNARNA--rrRNARNA--ttRNARNA
Information RepositoryInformation Repository“Hereditary Information”“Hereditary Information”
messenger RNAmessenger RNA
ribosomal RNAribosomal RNAtransfer RNAtransfer RNA
informationalinformationalStructuralStructuralcatalyticcatalytic
informationalinformationalstructuralstructural
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NucleotidesNucleotides3 components of monomer3 components of monomer
AdenineAdenineGuanineGuanineCytosineCytosine
UracilUracil/Thymine/Thymine
NitrogenousNitrogenousBaseBase PhosphatePhosphate
one or moreone or more
RiboseRiboseDeoxyDeoxyriboseribose
MonoMono--DiDi--TriTri--
SugarSugaraldoaldo Pentose Pentose
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Nitrogenousbase
Nucleoside
O
O
O−
−O P CH2
5’C
3’CPhosphategroup
Pentosesugar
(b) NucleotideFigure 5.26
O
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Nitrogenous BasesNitrogenous BasesFlatFlat Aromatic Aromatic NonNon--polarpolar
purinespurines33
22
1166
5577
44
88
99
pyrimidinespyrimidines11
33
22
44
55
66
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Polar Polar Edge: Edge: hydrogenhydrogen--bonding bonding edge edge Nitrogenous BasesNitrogenous Bases
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Assemble Nucleotides Assemble Nucleotides by by Condensation Dehydration Condensation Dehydration RxnsRxns..
nucleonucleosidesideuradineuradine
riboseribose uraciluracil 2’2’3’3’
1’1’4’4’
5’5’22
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445566
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Assemble Nucleotides Assemble Nucleotides by by Condensation Dehydration Condensation Dehydration RxnsRxns..
phosphatephosphate
nucleonucleotidetide
PhosphoPhospho--esterester
nucleosidenucleoside
Uridine Uridine monophosphatemonophosphate
(UMP)(UMP)
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PhosphoPhospho--anhydrideanhydride
ααββγ γ
ββ and and γγ are High energy bondsare High energy bonds
““carried” energy of ATP, GTP,CTP, UTPcarried” energy of ATP, GTP,CTP, UTP
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α α phosphatephosphate & & 3’ hydroxyl3’ hydroxylcan form can form didi--esterester
5’ to 3’ 5’ to 3’ phosphodiesterphosphodiesteris the basis of is the basis of
polynucelotide polynucelotide backbonebackbone 12
•• Nucleotide polymersNucleotide polymers– Are made up of nucleotides linked by
the ––OH group on the 3´ carbonOH group on the 3´ carbon of one nucleotide and the phosphate on the 5´phosphate on the 5´carbon on the next
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2’ OH2’ OH
2’ hydroxyl2’ hydroxylmakes RNAmakes RNAmore labilemore labile
in alkaline solutionsin alkaline solutions> pH 9> pH 9
2’2’deoxydeoxy
143’3’
5’5’ 3’3’
AntiparallelAntiparallelstrandsstrands
5’5’
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• The nitrogenous bases in DNA– Form hydrogen bonds in a complementary fashion (A with T only, and C with G only)
Why ?Why ?
Why not just HWhy not just H--bond with water ?bond with water ?165’5’
3’3’
3’3’
5’5’
BaseBasestackingstacking
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SugarSugar
SugarSugar
SugarSugar
5’5’POPO44
SugarSugar
POPO44
3’3’
POPO44
POPO445’5’
3’3’
polar
polar
polar
polar
polar
polarpolar
polar
hydrophobichydrophobic
hydrophobichydrophobic
hydrophobichydrophobic
hydrophobichydrophobic
Hydrophobic Interactions Hydrophobic Interactions –– driving force for double helixdriving force for double helix
Hydrogen bonding Hydrogen bonding –– stabilizes double helixstabilizes double helix 18
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ComplementaryComplementaryStrandsStrandsare theare the
Basis forBasis forfaithfulfaithful
copying copying ofofbase sequencebase sequencein the polymerin the polymer
The The sequencesequenceof basesof bases
ISISthe hereditarythe hereditaryinformationinformation
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Primary Structure:Primary Structure:Order of amino acids determined byOrder of amino acids determined by
a stretch of DNA sequencea stretch of DNA sequence
3 letter code3 letter code
64 possible64 possible“words”“words”
5’5’3’3’
gln serglu hisgln argthr stopala
TGA
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2
3
Synthesis ofmRNA in the nucleus
Movement of mRNA into cytoplasm
via nuclear pore
Synthesisof protein
NUCLEUS
CYTOPLASM
DNA
mRNA
Ribosome
AminoacidsPolypeptide
mRNA
Figure 5.2524
Summary:Summary:*Nucleotides and*Nucleotides and polynucleotidespolynucleotides*Numerous roles: *Numerous roles: informational,informational,
energy metabolismenergy metabolism, , signalingsignaling*Nucleotide composition: *Nucleotide composition:
nitrogenous basenitrogenous base, , pentose sugarpentose sugar, , & phosphates& phosphates
**RNARNA vs. vs. DNADNA: : structurallystructurally, , functionallyfunctionally
**PhosphodiesterPhosphodiester & & phosphoanhydridephosphoanhydride bondsbonds
**Double HelixDouble Helix:Base pairing & Base Stacking:Base pairing & Base Stacking
*Nucleic acid *Nucleic acid sequencesequence as informationas information
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Griffith: Griffith: something from bacteria transfers genetic traitsomething from bacteria transfers genetic trait
Avery, Avery, MacLeod and McCarty MacLeod and McCarty –– that somethingthat somethingis nucleic acid, not protein, carbohydrate or lipidis nucleic acid, not protein, carbohydrate or lipid
26Hershey & ChaseHershey & Chase
RadioactiveRadioactiveProteinProtein
Little Little RadioactivityRadioactivityin Offspringin Offspring
RadioactiveRadioactiveDNADNA
Most of the Most of the RadioactivityRadioactivityin Offspringin Offspring