有关我院医学本科生基础学习模块生物化学部分相关教师

BiochemistryLiEnmin有关我院医学本科生基础学习模块生物化学部分相关教师授课期间考察学生的决定以及实施参考意见为了教师在授课期间，加强对教学过程的有效管理与灵活操作，充分调动学生学习生物化学课程的积极性与主动性，经征求科教处同意，决定在生物化学授课期间由授课教师对学生的学习情况实施考察，并对每一个听课学生记录一个成绩，并将该成绩最终记入期末总成绩中。无故不来上课者扣分。上课时，未经请假提前早退者扣分。上课时，影响教师授课氛围者扣分。上课迟到者扣分。对上课讨论时主动发言，积极提问或出色完成授课教师所布置的作业或其它相关学习任务，且无上述不良情况者,每位教师根据具体情况可给予这样的学生鼓励加分并记入总成绩，但最终总成绩以100分为限。为了此项考查的客观公证性，使该举措真正发挥作用。特提出如下操作规则10.DNAreplication*11.RNAtranscription*12.Proteinbiosynthesis*13.Regulationofgeneexpression**14.GenerecombinationandgeneengineeringDNAsRNAs

Proteins10DNAreplication:entirety11RNAtranscription:systematicness12Proteinbiosynthesis:individuality10101211ChaptertenDNAreplication

Section1*GeneralfeaturesofDNAreplicationSection2*EnzymesinDNAreplicationSection3ProcessofDNAreplicationSection4ReversetranscriptionandothersSection5*DNAdamageandrepairConceptofDNAreplicationorDNAbiosynthesis

Thetransmissionofthegeneticinformations

betweenDNAandDNA

ThesynthesisofacomplementaryDNAstrandbyformingphosphodiesterlinkagesbetweennucleotidesbase-pairedtotemplatestrandiscatalyzedbylargemultienzymecomplexesreferredtoastheDNApolymerases

Semiconservativereplication

Section1GeneralfeaturesofDNAreplication1)

Experimentalbasisandthesignificanceofsemiconservativereplication*2)DNAreplicationisBidirectional

3)SemidiscontinuouspatternofDNAreplication

1)

ExperimentalbasisandthesignificanceofsemiconservativereplicationAcelebratedscientificexperiment

daughterDNAmoleculesparentDNAmoleculesparentDNAstrandDaughterornewDNAstrandtotalconservesemiconservecommingleThebasicexperimentconditionAexperimentaltable

Acentrifuge

AkindofbacteriumAfew14NH4ClculturesolutionsAfew15NH4ClculturesolutionsAfewsucroses7N14,15/1S22S22P3Theexperimentprocedurebacterium15cultureextractionbacteriumDNAcentrifugationDNADNADNAbacteriumbacteriumDNAlayerDNAlayerDNAlayerDNAlayerextractionextractionextractioncentrifugationcentrifugationcentrifugation14Nculture14Nculture14N1234totalconserveLL+H1515HLLLL+HL+HL+H14141414141514141414141415LL14/1514/1514/151514/1514/1514/15LMM+LM+LM+LHM+Lsemiconserve1414141414141414LLTheexperimentprocedurebacterium14cultureextractionbacteriumDNAcentrifugationDNADNADNAbacteriumbacteriumDNAlayerDNAlayerDNAlayerDNAlayerextractionextractionextractioncentrifugationcentrifugationcentrifugation15Nculture15Nculture15N123414/1514/1514151514/1515151514/151514/15151514/15HHLMM+HM+HM+HHM+Hsemiconserve

Significanceofsemiconservative

replicationGeneticconservativenessACGTTGCAACGTTGCAACGTTGCASection2EnzymesinDNAreplicationChemicalreactioninDNAreplication(dATP)m+(dCTP)n+(dGTP)y+(dGTP)z(dAMP+dCMP+dGMP+dGMP)m+n+y+z+(m+n+y+z)PPitopoisomeraseⅡsinglestrandbindingproteinA

CAGTGATCAGATGTCTCT5’OPPPHPPPHOOH3’5’A5’3’3’OOOHGhelicaseDNApolymeraseⅢDNApolymeraseⅠRNaseprimaseprimaseligasesinglestrandbindingprotein……dGTP/dTTP/dCTP/dTTPeukaryotepolymeras

*polymeras

polymeras

polymeras

*polymeras

prokaryotepolymerasIpolymerasIIpolymerasIII*

veriestreplicase

substitute

majoraction

proofread,repair,filling

majoraction

inmitochondria

DNApolymerases

proofread,repair,filling

substitute’’DNApolymeraseIIIofE.coliDNApolymeraseIofE.coliAGI1109kD,18Helix

2A-F:323aa,smallfragment,5’3’exonucleaseactivity3G-R/c-terminal:604aa,Klenowfragment,3’5’exonuclease

activity,5’3’polymeraseactivity,about20nucleotide.50aaHOECDBRNPLMQKJNCFGD+NPOH3'PP5'OH3'NP5'PN3’5’+PPi

PPN5'PNOH3'N3’5’DNApolymerasesfunction--15’3’polymeraseactivity

AG5’3’

PolymeraseI

PolymeraseII

PolymeraseI

PolymeraseIIPolymeraseIIIProofreading

cutthefragmentofprimerandmutatedfragments

**DNApolymerasesfunction--2exonuclease

activityCG5’3’GTCAA5’3’G5’3’(1)

ThestrictbasecomplementaryC5’3’T5’3’highfidelityofDNAreplicationTheconformationofDNApolymeraseIIIischangeable,asitsaffinitytonucleotideacids

(2)

thecharacterofDNApolymeraseselectingbase

AACGT5’3’ATGCATGCATGCATGCATGCGCATGCATGCTTT

(3)

TheproofreadingfunctionofDNApolymerase

A5’3’TA5’3’AA5’3’CA5’3’Gproofreading

DNAhelicase

DNAtopoisomerase

DNAsinglestrandbindingproteinhelicaseDnaA,DnaB(rep),DnaC……DnaXDnaBDnaCDnaADnaTDnaCDnaT

1234567891011helicaseDNApolimerase

positivesuperhelix

1234567891011negativesuperhelix1234567891011

topoisomerase

normalhelixDNAtopoisomeraseuntwistingtopoisomeraseI:breakssinglestrandDNA,notrequiresATPtopoisomeraseII:breaksdoublestrandsDNA,requiresATP

cutligatesinglestrandedDNA-bindingprotein,SSB

(1)

SSBisconsistof177aminoacidresiduesinE.coli(2)

tetrapolymer(3)

a

SSB=32nucleotides(4)

CooperativebindingDnaBSSBbank

TheroleofSSBtheactionsofprimerandprimase3’5’3’5’DNApolymeraseIII5’3’3’5’5’3’5’3’NewDNAstrand3’5’ParentalDNAtemplateprimaseSSBPrimaseandPrimosome

TheprimaseisaRNApolymerase,whichisdifferentwiththatinthetranscription.Theprimasesynthesizestheprimers,whichisusedinDNAsynthesis

TheprimerisafragmentofRNA

Thelengthofprimeris10-20bpapproximately

The

helicases

andotherreplicatedfactorshavebindedwithDNA,thentheprimase

havebindswiththemandformeda

primosomeatlast.3’3’5’5’

ATP

ADP+Pi3’3’5’5’

ligaseOHPOHPThecompareofseveralenzymes,whichinformationofphosphodiesterbondenzymesprovides3’-OHprovides5’-Presults1DNAprimerordNTP(dNMP)n+1

polymeraseextendingDNAstrand

2DNAnocontinuedtwosinglestrandsnocontinue

ligase

continue3DNAtobreakandputinordertwoputinordertoDNA

topoisomeraseDNAsinglestrandssuperhelicalstructure4primaseextendingprimerNTPprimerA

CAGTGATCAGATGTCTCT5’OPPPHPPPHOOH3’5’A5’3’3’OOOHGhelicaseDNApolymeraseⅢDNApolymeraseⅠRNaseprimaseprimaseligasesinglestrandbindingprotein……dGTP/dTTP/dCTP/dTTPPreparationFirst,youwillreadthesummaryineverychapters.Second,Tothebestofyourasmuchas,tounderstandthetablesandthefiguresineverychapters.Last,Findouttheproblemsinthem.ThedifferencesbetweentheprokaryoteandtheeukaryoteinDNAreplication?Section3ProcessofDNAreplicationMG1G2Scellcycleinitiationextensiontermination

1234InitiationofDNAreplicationProkaryoticcell(forinstanceE.coli)1

Afixedorigin(ori)

2

Bidirectionalreplication

Eukaryoticcellalotoforigintheta12origin2

1Oorigin2

1OO212

1OO3’3’DirectionDDDProkaryoticcellEukaryoticcellOriginHelicase,SSB...12laggingstrandsleadingstrands113172932445566166174

201209237245TGTGGATTA---TTATACACA------TTTGGATAA---TTATCCACAGATCTNTTTATTT---GATCTNTTNTATT---GATCTCTTATTACTheoriCofEcoli.palindromestructureDnaADnaBDnaBDnaCDnaCDnaTDnaTTheextensionofDNAreplication

rateofextension1prokaryoticcell,2500

bp/s。2eukaryoticcell

alotoforiginpolymeraseIIIholoenzymeprimerleadingstrandlaggingstrandpolymeraseIIIsubunit5’5’5’3’3’3’topoisomerasesinglestrandbindingproteintheterminationofDNAreplication

theterminatepointofE.coli

andSV40virusoriginterminatepointE.coliSV40

82%32%0%50%Ligase

3’5’3’5’PolIOHP3’5’3’5’RNaseOHP3’5’3’5’OHP3’5’3’5’ParentalDNAtemplatestrandRNAprimerNewDNAstrandtheroleofseveralenzymeinterminationofDNAreplication

degradationligationfillingOoriginOOOO3’3’DDDDDdirectionleadingstrandlaggingstrandOkazakifragmentsThe100--2000bpOkazakifragmentswasformedinDNAlaggingstrandinDNAreplication.

Rollingcirclereplication

13’OH5’3581023’5’945’3’67telomereandtelomeraseofeukaryotesstructureoftelomereTTAGGGTTAGGG……TTAGGGTTAGGGsequenceoftelomereTheendoflinearDNAinreplication5’3’5’CCCUAAGGGATTGGGATTstructureoftelomeraseRNARTaseTP15’3’3’5’CCCUAAGGGATTGGGATTmechanismoftelomerase5’3’3’5’CCCUAAGGGATTGGGATT5’3’3’5’CCCUAATTGGGATT5’3’3’5’CCCUAATTGGGATT5’3’3’5’CCCUAATTGGGATT5’3’12343’5’CCCUAATTGGGATT5’3’3’5’CCCUAATTGGGATT5’3’5n3’5’5’3’TTGGGATT3’5’5’3’TTGGGATT3’5’5’3’TTGGGATTTTGGGATT3’5’3’5’123Section4Reversetranscriptionandothers

singleRNAstrandRNA-DNAdoublestrandssingleDNAstrandDNAdoublestrandsRTaseRNaseHRTaseRNA3’5’

5’3’5’3’RTaseRTase5’3’5’3’RNaseH5’3’integration

synthesizecDNA

frommRNAAAA…AAA5’3’mRNAAAA…AAA3’5’

AAA…AAATTT...TTT5’3’5’3’primer:oligodTreverse

transcriptaseTTT...TTT5’3’basichydrolysisTTT...TTT5’3’?TTT...TTT5’3’AAA…AAADNApolymeraseITTT...TTT5’3’AAA…AAA3’5’S1nucleasesignificanceofreversetranscription?Section5DNAdamageandrepairmutationsTheyareheritable

permanentchangesinthebasesequenceofDNA.DNAdamagetheeffectofmutation3

Lethal

4

Onlylostsomefunction1

Useful2

Theremaybesomeeffecttothegenotype,andnoornotdetectableeffecttothephenotypecauseofmutation1spontaneousmutation

mechanism?frequency1/109

2physical

3chemical

4biologicalInducedmutationmutationaltypes1

mismatch/pointmutation2

deletion3

insertion4

rearrangement/inversion

pointmutation1)

transition2)

transversion

transitionAgivenpyrimidineischangedtotheotherpyrimidine,oragivenpurineischangedtotheotherpurine.

transitionC

TT

CG

AA

GCGCGT1CA

T

TACAC2CTCGCCCA3CTAATCTG4CCGATGCCCCTAGGTCTCCTGTGGCTGGGCCTAGCCCTGTTGGGGGCTCTGCATGCCCAGGCCCAGGACTCCACCTCAGACCTGATCCCAGCCCCACCTCTGAGCAAGGTCCCTCTGCAGCAGAACTTCCAGGACAACCAATTCCAGGGGAAGTGGTATGTGGTAGGCCTGGCAGGGAATGCAATTCTCAGAGAAGACAAAGACCCGCAAAAGATGTATGCCACCG*TCTATGAGCTGAAAGAAGACAAGAGCTACAATGTCACCTCCGTCCTGTTTAGGAAAAAGAAGTGTGACTACTGGATCAGGACTTTTGTTCCAGGTTGCCAGCCCGGCGAGTTCACGCTGGGCAACATTAAGAGTTACCCTGGATTAACGAGTTACCTCGTCCGAGTGGTGAGCACCAACTACAACCAGCATGCTATGGTGTTCTTCAAGAAAGTTTCTCAAAACAGGGAGTACTTCAAGATCACCCTCTACGGGAGAACCAAGGAGCTGACTTCGGAACTAAAGGAGAACTTCATCCGCTTCTCCAAATCTCTGGGCCTCCCTGAAAACCACATCGTCTTCCCTGTCCCAATCGACCAGTGTATCGACGGCTGASequenceofNGALgeneinSHEECcell223AG,75IV

transvertionTransversionsarechangesfromapyrimidinetoeitherofthetwopurines,andorthechangesofapurineintoeitherofthetwopyrimidines.C

GC

AT

GT

Atransversion

CGCGG1CCGCGCGA2CTATACAG3CTATACAA4CCGA

CA

TG

CG

TATCTC5CGCATCTT6CTTGCCCC7CGCGCCCT8CATHbA

HbS

genepeptidegenepeptideGluValCTCCACGAGGTG17TA,6GluValpointmutation

CA

CGTATGACATGCGT

transversions

transitionsCTTCAGGAdeletedmutationinsertedmutationinversedmutation5’5’3’3’5’5’3’3’OHOHOHOH

PPPP5’5’3’3’OHPP5’5’3’3’OHOHOHPPrearrangement12Hb

genesfamilyin11chromosome12121212Hbanti-LeporeHbLeporetwogenetypesofMedanaemiarepairofDNAdamaged1

photoreactivationrepair2

excisionrepair3

recombinationrepair4

SOSrepair

PhotoreactivationrepairOOOOPHNNRHNNRCH3CH3UVphotolyase300-600nmOOORPHNNRCH3OHNCH3N

excisionrepairaffectfactorspecificendo-nucleases3’5’ligase5’3’5’3’pol1UvrAUvrBUvrC

recombinationrepairpolIligaseRecASOSrepair

TheDNAisdamagedgravelyandextensively.ThereplicationofDNAhadbeenstoped.TheSOSrepairisaemergencystep.TheSOSrepairisacomplicatednetworkofregulation.TherateofDNAmutationisstillveryhigh.

TheSOSrepairiscallederrorpronerepair.练习题DNA复制1、DNA复制时，下列哪一种酶是不需要的？

ADNA指导下的DNA聚合酶

BDNA连接酶

C拓扑异构酶

D解链酶

E限制性内切酶2、合成DNA的原料是

AdNMA

BdNDP

CdNTP

DNTPENMP3、真核细胞进行DNA复制的部位是

A

细胞膜

B

细胞浆

C

细胞核

D

核蛋白体

E微粒体

原核细胞进行DNA复制的部位是其拟核区

A由DNA为模板合成的DNA片段

B

由DNA为模板合成的RNA片段

C

由RNA为模板合成的DNA片段

D

由RNA为模板合成的RNA片段

4、DNA复制中的引物是

A5’-TCTA-3’B5’-ATCT-3’C5’-UCUA-3’D5’-GCGA-3’E3’-TCTA-5’5、DNA复制时，模板序列5’-TAGA-3’

将合成哪种互补序列？

6、关于