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Biochemistry Li Enmin

Biochemistry Li Enmin. 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。. 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. 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。

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Biochemistry Li Enmin

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  1. Biochemistry Li Enmin

  2. 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。

  3. 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 • 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。

  4. 10. DNA replication* 11. RNA transcription* 12. Protein biosynthesis* 13. Regulation of gene expression** 14. Gene recombination and gene engineering

  5. DNAs RNAsProteins 10 12 11 10 10 DNA replication: entirety 11 RNA transcription: systematicness 12 Protein biosynthesis: individuality

  6. Chapter ten DNA replication

  7. Section 1* General features of DNA replication Section 2* Enzymes in DNA replication Section 3 Process of DNA replication Section 4 Reverse transcription and others Section 5* DNA damage and repair

  8. Concept of DNA replication or DNA biosynthesis The transmission of the genetic informations between DNA and DNA The synthesis of a complementary DNA strand by forming phosphodiester linkages between nucleotides base-paired to template strand is catalyzed by large multienzyme complexes referred to as the DNA polymerases Semiconservative replication

  9. Section 1 General features of DNA replication 1)Experimental basis and the significance of semiconservative replication* 2) DNA replication is Bidirectional 3) Semidiscontinuous pattern of DNA replication

  10. 1) Experimental basis and the significance of semiconservative replication

  11. A celebrated scientific experiment

  12. parent DNA strand parent DNA molecules Daughter or new DNA strand daughter DNA molecules total conserve commingle semi conserve

  13. The basic experiment condition • A experimental table • A centrifuge • A kind of bacterium • A few 14NH4Cl culture solutions • A few 15NH4Cl culture solutions • A few sucroses 7N14,15 / 1S22S22P3

  14. The experiment procedure 1 2 3 4 culture culture culture bacterium15 bacterium bacterium bacterium 14N 14N 14N extraction extraction extraction extraction DNA DNA DNA DNA centrifugation centrifugation centrifugation centrifugation DNA layer DNA layer DNA layer DNA layer

  15. total conserve 14 L L 14 L 14 14 14 H L+H 14 L 14 L 15 14 L+H 14 L 14 15 L+H 14 15 L+H 15

  16. semi conserve 14 14/15 M+L 14/15 M+L 14/15 14 H M M+L 14 L 14 15 L 14 14/15 M+L 14/15 14/15 14 14 L 14

  17. The experiment procedure 1 2 3 4 culture culture culture bacterium14 bacterium bacterium bacterium 15N 15N 15N extraction extraction extraction extraction DNA DNA DNA DNA centrifugation centrifugation centrifugation centrifugation DNA layer DNA layer DNA layer DNA layer

  18. semi conserve 15 15 H 15 M+H 14/15 15 L M M+H 14/15 M+H 14/15 14 15 14/15 M+H H 14/15 14/15 15 15 H 15

  19. Significance of semiconservative replication TGCA ACGT TGCA ACGT TGCA ACGT Genetic conservativeness

  20. Section 2 Enzymes in DNA replication

  21. Chemical reaction in DNA replication (dATP)m + (dCTP)n + (dGTP)y + (dGTP)z (dAMP + dCMP + dGMP + dGMP) m +n+ y+z + (m + n + y + z) PPi

  22. helicase 5’ 3’ A C A G T G A T C A G A 5’ T G T C T C T 3’ primase primase H O P P P A G OH single strand binding protein O P PP HO O DNA polymerase Ⅲ ……dGTP/dTTP/dCTP/dTTP RNase DNA polymerase Ⅰ ligase O H 3’ 5’ single strand binding protein topoisomeraseⅡ

  23. DNA polymerases prokaryote polymeras I polymeras II polymeras III* proof read, repair, filling proof read, repair, filling veriest replicase substitute substitute eukaryote polymeras * polymeras  polymeras polymeras* polymeras  major action major action in mitochondria

  24.          ’   ’         DNA polymerase III of E. coli

  25. DNA polymerase I of E. coli 50 aa H G B G C I A E F K C J D D R L N Q O M N P 1 109kD, 18  Helix 2 A-F: 323 aa, small fragment, 5’3’ exonuclease activity 3 G-R/c-terminal: 604 aa, Klenow fragment , 3’ 5’ exonuclease activity, 5’ 3’ polymerase activity, about 20 nucleotide.

  26. DNA polymerases function--1 5’3’ polymerase activity 5’ 3’ N N N + OH3' OH3' 5' P P P 5' P P    5’ 3’ N N N OH3' 5' P P P + PPi

  27. DNA polymerases function--2 exonuclease activity cut the fragment of primer and mutated fragments * Polymerase I Polymerase II 5’ 5’ * Polymerase I Polymerase II Polymerase III Proof reading C A 3’ 3’ G G

  28. high fidelity of DNA replication (1)The strict base complementary 5’ 5’ 5’ 5’ 3’ 3’ 3’ 3’ G G A C T T A C

  29. (2)the character of DNA polymerase selecting base 5’ T A A A T T A A T T A A T T T T The conformation of DNA polymerase III is changeable, as its affinity to nucleotide acids G 3’ C C G A A C G T C G C G C G G C C C G G T

  30. (3)The proof reading function of DNA polymerase proof reading 5’ 5’ 5’ 5’ A C G 3’ 3’ 3’ 3’ T A A A A

  31. DNA helicase • DNA topoisomerase • DNA single strand binding protein

  32. helicase Dna A, Dna B (rep), Dna C……Dna X Dna T Dna C Dna B Dna A Dna C Dna T

  33. DNA topoisomerase normal helix helicase positive superhelix 1 2 3 4 5 6 7 8 9 10 11 1 2 3 4 5 6 7 8 9 10 11 DNA polimerase 1 2 3 4 5 6 7 8 9 10 11 topoisomerase negative superhelix

  34. ligate cut untwisting topoisomerase I: breaks single strand DNA, not requires ATP topoisomerase II: breaks double strands DNA, requires ATP

  35. single stranded DNA-binding protein, SSB (1)SSB is consist of 177 amino acid residues in E.coli (2)tetrapolymer (3) a SSB= 32 nucleotides (4) Cooperative binding

  36. The role of SSB Dna B SSB bank

  37. the actions of primer and primase Parental DNA template 5’ 3’ SSB primase 5’ 3’ 5’ 3’ 5’ 3’ 5’ 3’ DNA polymerase III 5’ 3’ 3’ 5’ New DNA strand

  38. Primase and Primosome The primase is a RNA polymerase, which is different with that in the transcription.  The primase synthesizes the primers, which is used in DNA synthesis The primer is a fragment of RNA The length of primer is 10-20bp approximately The helicasesand other replicated factors have binded with DNA, then the primase have binds with them and formed a primosome at last.

  39. ligase 3’ 5’ P OH P OH 5’ 3’ ATP ADP+Pi 3’ 5’ 5’ 3’

  40. The compare of several enzymes, which in formation of phosphodiester bond enzymes results provides 3’-OH provides 5’-P 1 DNA primer or dNTP (dNMP) n+1 polymerase extending DNA strand 2 DNA no continued two single strands no continue ligase  continue 3 DNA to break and put in order two put in order to DNA topoisomerase DNA single strands superhelical structure 4 primase extending primer NTP primer

  41. helicase 5’ 3’ A C A G T G A T C A G A 5’ T G T C T C T 3’ primase primase H O P P P A G OH single strand binding protein O P PP HO O DNA polymerase Ⅲ ……dGTP/dTTP/dCTP/dTTP RNase DNA polymerase Ⅰ ligase O H 3’ 5’

  42. Preparation • First, you will read the summary in every chapters. • Second, To the best of your as much as, to understand the tables and the figures in every chapters. • Last, Find out the problems in them.

  43. The differences between the prokaryote and the eukaryote in DNA replication ?

  44. Section 3 Process of DNA replication

  45. termination G2 2 3 M S extension 4 G1 initiation 1 cell cycle

  46. Initiation of DNA replication Prokaryotic cell ( for instance E.coli) 1A fixed origin (ori) Eukaryotic cell a lot of origin 2Bidirectional replication

  47. origin theta 1 2 O O O D D 3’ 21 2 1 21 21 3’ D Direction origin O O Eukaryotic cell Prokaryotic cell

  48. leading strands Helicase, SSB ... Origin 2 1 lagging strands

  49. The oriC of E coli. GATCTNTTTATTT---GATCTNTTNTATT---GATCTCTTATTAC 55 66 166 174201 209 237 245        1 13 17 29 32 44 TGTGGATTA---TTATACACA------TTTGGATAA---TTATCCACA palindrome structure DnaT DnaC DnaB DnaB DnaA DnaC DnaT

  50. The extension of DNA replication rate of extension 1 prokaryotic cell, 2500 bp/s。 2 eukaryotic cell a lot of origin

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