第六章 基因的表达与调控 ( 上 ) 原核基因表达调控模式
DESCRIPTION
第六章 基因的表达与调控 ( 上 ) 原核基因表达调控模式. 自然选择倾向于保留高效率的生命过 程。在每 30 分钟增殖一次的 10 9 细菌群体 中,若一个细菌变成 29.5 分钟增殖,经 过 80 天的连续生长后,这个群体中的 99.9% 都将具有 29.5 分钟增殖一倍的生 长速度。. 原核生物细胞的基因和蛋白质种类较 少,如大肠杆菌基因组约为 4.20 × 10 6 bp 共有 4 288 个开放读码框(表 6-1 )。据估 计,一个细胞中总共含有 10 7 个蛋白质分 子 。. 表 6-1 大肠杆菌、伤寒杆菌和尿殖道支原体基因组 - PowerPoint PPT PresentationTRANSCRIPT
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()3010929.580 99.9% 29.5
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4.20106bp4 2886-1107
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6-1
4288172747013168110354558531923784172431123118830648256DNA115873296717864755271218214110142712334
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15 00050DNARNAconstitutive
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adaptive or regulated15-
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6. 1 DNA-DNAgeneexpressiongene regulationgenecontrol
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6-1RNADNARNA
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transcriptionalregulation post-transcriptionalregulation1mRNAdifferentialprocessing of RNA transcrpt2differential translationof mRNA
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coupled transcription andtranslationprimary transcript6-2
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repressor
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activator6-36-2
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6-3 a. b. c. d.
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7046-424DNA2DNA
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6-4 70
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54DNA-24-126-570DNA54TATATBP
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6-5 70 54
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6. 2 lactoseoperon 3 Z Y A
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3Z-Y-A-
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-- - ---A-
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6. 2. 1 lac
lac+-1 2 6%7%105/
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lac+-32P mRNA DNA 12-lac mRNA lac mRNA
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IPTG TMGO-ONPG gratuitousinducer
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35S35S--35S
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6. 2. 2 Jacob Monod
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6-9 Lac
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A. ZYAmRNAB. mRNAPIOC. DNA26bpD. lac mRNAE. lac mRNA
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6-10 LacmRNA-
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lac Ilac mRNA 43471 IPTG , 510
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-lac6-11
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-6-laclac mRNAcatabolite repression
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cAMPcAMPATP
cAMPcAMP
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CrpcAMP CRPcAMPlac mRNAcAMP-CRP lac
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6-13 gallac araCRP-cAMP
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(catabolitesensitive operoncAMP-CRP
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6-14 lacCRP-cAMP-35-10
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cAMP-CRPlac mRNADNA-RNARNA
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6-15CRP-cAMP DNA DNA >90
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6. 2. 3 lacPO
PImRNA5-10bpO-7+28+11
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6-16 O
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6. 2. 4 lac
1lac-1 0.5 0.2 -
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lac mRNAmRNA5'3'
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lac mRNAAZZA
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2purlacT6tsxpurlaclac
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6. 3 trpcAMP-CRP576-17
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6-17
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trpEtrpGtrpDtrpFtrpCtrpAtrpBtrpEtrpGtrpCtrpB
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trpEtrpEtrpLtrpa
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trptrpRtrp259065trpStRNAtRNATrptrp
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6. 3. 1 trptrpRtrp mRNAaporepressortrp mRNA
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trp
DNAtrp
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6. 3. 2
1 trp mRNA 5 162bp mRNA 123150trp6-10mRNA 140RNAtrpmRNA-
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2AUGUGA14101177
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3mRNAtrp412341-23-42-3
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RNaseT1RNAtrp1-23-43-4 6-23
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4tRNATrp 41trp 2-33-4
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423-4 - RNA
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6-24 trp
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trp
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mRNA
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6. 4 6. 4. 1 galactoseoperon173UDP-galactose-4-epimerasegalE-galactose transferasegalTgalactose kinasegalK-1-
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galR 55 lac galR galE T K O galRgalOlacI-lacOgalR- galOc ETKgal
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gal mRNAOP-67-73galE
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1cAMP-CRPgal
galgal
gal P-O 5bpgalRNAS1S2
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S1RNAS1CRP cAMP cya- cAMP crp- gal S1 cAMP-CRPS1cAMP-CRPS2
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2gal UDPgalgalactose epimerasegalEUDP-UDPgal
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S1cAMP-CRP S2
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6. 4. 2 araB araA araD araBADaraBaraAL-araDL--5--4- araEaraF
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araBAD O1 O2 araC lac gal cAMP-CRP AraC
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araBADaraCaraBADPBADaraCPc6-27
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6-27 ara
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araaraBADmRNAcrp-araBAD mRNAPBADcAMP-CRP
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AraCPBADPrPiPBADPrAraCPi
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a. AraC Pc araCb. AraC O2ara IDNAaraBADc. AraCaraO1araICRP-cAMP
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a.cAMP-CRPAraCPrARNAPcaraC
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b.cAMP-CRPAraCPrBaraBAD mRNA
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c.araCPiBAcAMP-CRParaCaraBAD
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6. 4. 3 histidineHishuthistidine utilizing enzymehutoperon6-30
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Hut44hutGhutHhutIhutUhutChutIhutGhutChutUhutHmRNA6-31
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hutRNAhuthutcAMP-CRP
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6. 4. 4 LexASOSDNASOS DNASOS DNALexASOSLexA
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6-32 LexASOSDNA
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1000RecADNADNARecADNALexADNASOSrecADNA
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6. 4. 5 two-component systems sensor protein responseregulator protein
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6-33
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6. 4. 6
1rRNArRNArrnEP1P2P1P235ppGppP1rRNAP2rrnE
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2S1SIrpsArpsA4P1P2S1P3P4P1P2ppGppP3P4S1
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3DnaQDnaQDNARNAP2RNAP1 DnaQP2RNAP1
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6. 5 1.5101021085108108
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6. 5. 1 Rhizobium trifolii
R. phaseoliR. Leguminosarum
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6-5
R. melilotiR. trifoliiR.leguminosarumR. phaseoliB. lupiniB. japonicumCowpearhizobia
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6. 5. 2 8e-N2+8H++32ATP------>2NH3+H2+32ADP+32PiI5.01046.0104nifDnifK4[4Fe-4S]-FeMoCoFeMo-protein
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II3.0104nifHFe-proteinII[4Fe-4S]
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FeMoCo1 Mo6Fe8S-FeMoCo191195191195
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6-6
CAGTCCCTGGCCACCACATC40.618.7DJ357 nifDK Kmr048.5DJ178 -His195 AsnCAGTCCCTGGCAACCACATC3.726.3DJ255 -Gln191LysCGCGGCGTTTCCAAGTCCCTG1.439.5
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6. 5. 3
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nifALnifAnifnifADNA nif
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nifAnifLnifnifLnifA nifNH3 O2 NifUNF92810mmol/L NH4+ UNF714 nifAL
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nifADNApMC73AUNF71410/ NH4+15%30%
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6-7 nifA
/ NH4++NH4+UNF9281000.005UNF71400UNF714+pMC73A23027UNF714+pMC73B0.10.1UNF1780(glnA100nif)0.050.075UNF1780+pMC73A17480UNF1780+pMC73B0.0050.005
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nif-90ntrBntrCntrnitrogenregulation70ntrAnifAntrAntrCnifntrCNH3NH3ntrC
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- UMPglnDGlnB GlnB UMP UMPGlnBNtrBNtrCnifAL
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GlnBNtrBNtrCnif6-38
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O2LbLbO2O2O2
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6-9
Lb300mol/L3 000mol/LLb0.20.260mol/L600mol/L11nmol/L11nmol/L/5 50055 000
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6. 5. 4 nts382
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6-10 Bragg
/Bragg/nts38218+5nts382/Bragg201+35
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6-11
/Nts382 / BraggBragg / nts3820360+4935+41089+1842+620114+2437+440177+2835+560312+3530+6
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6. 6 6. 6. 1 mRNARBS----AUGRBSSD16S rRNA 3 mRNARBSSDAUGSDAUG4109
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6. 6. 2 50dnaG2 800rpoD40 000rpsU
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dnaG6-12AUAdnaG
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6-12
AUU%AUC%AUA%3762126740DnaG363232
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LacIAraCTrpRdnaGtRNA
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6. 6. 3 trp5trpEtrpDtrpBA trpE trpD trpB trpAtrpEtrpD
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trpEACU UUC UGA uggcuAUG GCUtrpD
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trpBtrpA
trpBGAA AUC UGAuggaaAUGGAAtrpA
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galgalTgalK3galKSDgalTgalTSDgalK