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SINTESIS DNA ALUR INFORMASI GENETIK Flow of information replication DNA  DNA transcription  RNA translation  protein.

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Presentasi berjudul: "SINTESIS DNA ALUR INFORMASI GENETIK Flow of information replication DNA  DNA transcription  RNA translation  protein."— Transcript presentasi:

1

2 SINTESIS DNA

3 ALUR INFORMASI GENETIK

4 Flow of information replication DNA  DNA transcription  RNA translation  protein

5

6

7 dsDNA 5’ 3’ antiparallel dsDNA is always antiparallel

8 complementary GGATGCGT 3’-CCTACGCA-5’ Two ssDNA molecules joined by standard base-pairing rules In dsDNA, the strands are always complementary. TB 5’- -3’

9 Bacterial DNA replication DNA synthesis using a DNA template Complementary base pairing (A=T, G  C) determines the sequence of the newly synthesized strand. DNA replication always proceeds from 5’ to 3’ end.

10 REAKSI PERPANJANGAN

11 Overview of bacterial DNA replication single origin (in bacteria) bidirectional theta structures replication fork semi-conservative TB

12 bacterial DNA replication bacterial chromosome origin (start point) bidirectional

13 two replication forks theta structure

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15 semi-conservative + **** * *

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17 Enzim yang terlibat dalam Replikasi SSB (ssDNA binding protein) Binds to and stabilizes ssDNA

18 helicase Unwinds duplex DNA

19 ssDNA binding protein binds to and stabilizes ssDNA prevents base pairing ssDNA binding protein

20 All DNA polymerases require a primer DNA is synthesized 5' to 3' Important facts TB

21 Template A sequence of DNA or RNA that directs the synthesis of a complementary sequenceA sequence of DNA or RNA that directs the synthesis of a complementary sequence The initial segment of a polymer that is to be extended on which elongation dependsThe initial segment of a polymer that is to be extended on which elongation depends Primer

22 primase synthesizes a short RNA primer using a DNA template RNA primer (a short starting sequence made of RNA) primase TB

23 Polimerase Memerlukan primer dan cetakan DNAMemerlukan primer dan cetakan DNA Polimerisasi diperpanjang pada 3’Polimerisasi diperpanjang pada 3’ Aktivitas eksonuklease 3’-5’, berfungsi sebagai proofreadingAktivitas eksonuklease 3’-5’, berfungsi sebagai proofreading Aktivitas eksonuklease 5’-3’ untuk menghilangkan primerAktivitas eksonuklease 5’-3’ untuk menghilangkan primer

24 DNA polymerase III Synthesizes DNA from a DNA template and proofreads TB DNA polymerase I Synthesizes DNA from a DNA template and removes RNA primers.

25 DNA ligase Joins DNA strands together by forming phosphodiester bonds DNA ligase

26 replication fork 5' 3' template strands lagging strand leading strand

27 helicase ssDNA binding proteins RNA primer 3' 5' Leading strand synthesis

28 helicase ssDNA binding proteins DNA polymerase 3' 5'

29 helicase ssDNA binding proteins DNA pol III 3' 5' Leading strand synthesis DNA

30 helicase ssDNA binding proteins (primase) pol III 3' Lagging strand synthesis (discontinuous) Okazaki fragment (~1000 bases) 3' 5'

31 Primer removal pol III pol I 3' 5' 5’ to 3’ exonuclease activity

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33 Proofreading Pol III removes misincorporated bases using 3' to 5' exonuclease activity This decreases the error rate to about per base pair inserted

34 Ligase DNA Menyambung dua fragmen Okasaki dengan membentuk ikatan fosfodiester antara 3’-OH fragmen 1 dengan 5’-P fragmen 2Menyambung dua fragmen Okasaki dengan membentuk ikatan fosfodiester antara 3’-OH fragmen 1 dengan 5’-P fragmen 2

35 DNA ligase Ligation

36 KEPERLUAN REPLIKASI DNA TEMPLATE (CETAKAN)TEMPLATE (CETAKAN) PRIMER : 3’-OH - PERPANJANGANPRIMER : 3’-OH - PERPANJANGAN PREKURSOR : dNTPPREKURSOR : dNTP Enzim : polimerase DNA, helikase, primase, SSBP, ligaseEnzim : polimerase DNA, helikase, primase, SSBP, ligase

37 5 3 5

38 Lokus awal replikasi (Ori)

39 INISIASI

40 Prokaryotic vs. Eukaryotic Bacterial cells have one giant looped chromosomeBacterial cells have one giant looped chromosome Replication can occur in one or two directionsReplication can occur in one or two directions –One origin of replication In Eukaryotes many origins of replication existIn Eukaryotes many origins of replication exist –These form replication bubbles –Eventually bubbles meet and replication is done –Replication forks - where DNA is opened up

41 REPLIKON E.coli

42 REPLIKON MAMALIA

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44 Since all known DNA polymerases need a primer, how are the ends of linear DNA replicated in eukaryotes? 5' 3' RNA primer template newly synthesized DNA Replication of the ends of linear DNA

45 repetitive DNA at the end of linear eukaryotic chromosomes Telomeres (GGGGTT) n Example n = GGGGTT 5'

46 Telomerases are enzymes that add DNA repeats to the 3' end of DNA. Telomerases are composed of protein and an RNA molecule that functions as the template for telomere synthesis. AACCCCAAC telomerase

47 Human telomerase Telomerase = ribonucleoprotein complexTelomerase = ribonucleoprotein complex –Ribo = ribosomal/RNA association –Nucleo = nuclear localization –Protein = contains a protein Responsible for maintaining telomere length in eukaryotic chromosomesResponsible for maintaining telomere length in eukaryotic chromosomes Main components:Main components: –Telomerase reverse transcriptase –Human telomerase RNA (hTR)

48 Human telomerase (2) Reverse transcriptaseReverse transcriptase –Transcribes RNA to DNA (rather than the usual DNA to RNA) Telomeres – repeated regions at the end of eukaryotic chromosomesTelomeres – repeated regions at the end of eukaryotic chromosomes hTR is the template for the repeated regionhTR is the template for the repeated region

49 Human telomerase (3) hTR 11-nt templating region consists of:hTR 11-nt templating region consists of: –Repeat template: CUAACCC –Alignment domain: UAAC Positions telomerase on the DNA strandPositions telomerase on the DNA strand Provides template for repeat regionProvides template for repeat region

50 AACCCCAAC 5' GGGGTT 5' telomerase

51 AACCCCAAC 5' GGGGTT primase GGGGTT

52 pol III pol I 5' ligase telomeric repeats

53 For most cells, telomeres are added during development. Later telomerase becomes inactive. Hence, as cells divide the DNA becomes shorter. Note that telomerase is reactivated in many types of cancer cells.

54 INHIBITOR TOPOISOMERASE ANTIBIOTIK QUINOLON : MENGHAMBAT TOPOISOMERASE BAKTERI GRAM NEGATIF, MODIFIKASI BAKTERI GRAM POSITIF DAN AEROBIK Camptothecin : INHIBITOR TOPOISOMERASE I SEBAGAI ANTI KANKER DENGAN MENSTABILKAN BENTUK ENZIM TERIKAT PADA DNA SECARA KOVALEN

55 TOPOISOMERASE SBG TARGET Novobiocin – subunit ATPase GyrBNovobiocin – subunit ATPase GyrB Asam naladiksat – Gyr AAsam naladiksat – Gyr A Ciprofloxacin (oral) – stop replikasiCiprofloxacin (oral) – stop replikasi MENGGANGU PROSES PEMOTONGAN DAN PENYAMBUNGAN UNTAI DNA


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