fig. 16-9-3

26
Fig. 16-9-3 A T G C T A T A G C (a) Parent molecule A T G C T A T A G C (c) “Daughter” DNA molecules, each consisting of one parental strand and one new strand (b) Separation of strands A T G C T A T A G C A T G C T A T A G C It looks so simple…..

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It looks so simple…. A. T. A. T. A. T. A. T. C. G. C. G. C. G. C. G. Fig. 16-9-3. A. T. A. T. A. A. T. T. T. A. T. A. T. T. A. A. C. C. G. C. G. C. G. G. (c) “Daughter” DNA molecules, each consisting of one parental strand and one new strand. - PowerPoint PPT Presentation

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Page 1: Fig. 16-9-3

Fig. 16-9-3

A T

GC

T A

TA

G C

(a) Parent molecule

A T

GC

T A

TA

G C

(c) “Daughter” DNA molecules, each consisting of one parental strand and one new strand

(b) Separation of strands

A T

GC

T A

TA

G C

A T

GC

T A

TA

G C

It looks so simple…..

Page 2: Fig. 16-9-3

DNA Pol III

DNA polymerase III (from E. coli)- Enzyme responsible for almost all DNA replication- Extends DNA polymers by adding nucleotides to 3’ ends

Page 3: Fig. 16-9-3

DNA Pol III

DNA polymerase III (from E. coli)- Enzyme responsible for almost all DNA replication- Extends DNA polymers by adding nucleotides to 3’ ends

Requires:1.Template strand of DNA2.“Primer” strand of DNA

Page 4: Fig. 16-9-3

DNA Pol III

DNA polymerase III (from E. coli)- Enzyme responsible for almost all DNA replication- Extends DNA polymers by adding nucleotides to 3’ ends

Requires:1.Template strand of DNA2.“Primer” strand of DNA3.Deoxynucleoside triphosphates

dATP

Page 5: Fig. 16-9-3

deoxynucleotide triphosphates (dNTPs)i.e. dATP, dGTP, dCTP, dTTP

The fundamental building blocks for DNA synthesis

Page 6: Fig. 16-9-3

DNA Pol IIIDNA synthesis

Page 7: Fig. 16-9-3

DNA Pol III

Page 8: Fig. 16-9-3

Fig. 16-9-3

A T

GC

T A

TA

G C

(a) Parent molecule

A T

GC

T A

TA

G C

(c) “Daughter” DNA molecules, each consisting of one parental strand and one new strand

(b) Separation of strands

A T

GC

T A

TA

G C

A T

GC

T A

TA

G C

It looks so simple…..

Page 9: Fig. 16-9-3

Fig. 16-12a

Origin of replication Parental (template) strand

Daughter (new) strand

Replication fork

Replication bubbleDouble-stranded DNA molecule

Two daughter DNA molecules

(a) Origins of replication in E. coli

0.5 µm

Prokaryotic replication

Page 10: Fig. 16-9-3

Fig. 16-13

Topoisomerase

Helicase

PrimaseSingle-strand binding proteins

RNA primer

55

5 3

3

3

3’

DNA needs to be made single stranded (and kept that way)

Page 11: Fig. 16-9-3

Fig. 16-13

Topoisomerase

Helicase

PrimaseSingle-strand binding proteins

RNA primer

55

5 3

3

3

DNA synthesis is initiated by Primase making a short RNA “primer”

Page 12: Fig. 16-9-3

Fig. 16-15b

Origin of replication

RNA primer

“Sliding clamp”

DNA pol IIIParental DNA

3

5

5

5

5

5

5

3

3

3

Page 13: Fig. 16-9-3

Fig. 16-12a

Origin of replication Parental (template) strand

Daughter (new) strand

Replication fork

Replication bubbleDouble-stranded DNA molecule

Two daughter DNA molecules

(a) Origins of replication in E. coli

0.5 µm

Prokaryotic replication

Page 14: Fig. 16-9-3

Fig. 16-15a

Overview

Leading strand

Leading strandLagging strand

Lagging strand

Origin of replication

Primer

Overall directions of replication

Page 15: Fig. 16-9-3

Fig. 16-16a

Overview

Origin of replication

Leading strand

Leading strand

Lagging strand

Lagging strand

Overall directions of replication

12

Page 16: Fig. 16-9-3

Fig. 16-16b1

Template strand

5

53

3

Primase

Page 17: Fig. 16-9-3

Fig. 16-16b2

Template strand

5

53

3

RNA primer 3 5

5

3

1

Primase

DNA Pol III + S. clamp

Page 18: Fig. 16-9-3

Fig. 16-16b3

Template strand

5

53

3

RNA primer 3 5

5

3

1

13

35

5

Okazaki fragment

Primase

DNA Pol III + S. clamp

Page 19: Fig. 16-9-3

Fig. 16-16b4

Template strand

5

53

3

RNA primer 3 5

5

3

1

13

35

5

Okazaki fragment

12

3

3

5

5

Primase

DNA Pol III + S. clamp

Page 20: Fig. 16-9-3

Fig. 16-16b5

Template strand

5

53

3

RNA primer 3 5

5

3

1

13

35

5

Okazaki fragment

12

3

3

5

5

12

3

3

5

5

Primase

DNA Pol III + S. clamp

DNA Pol I

Page 21: Fig. 16-9-3

Fig. 16-16b6

Template strand

5

53

3

RNA primer 3 5

5

3

1

13

35

5

Okazaki fragment

12

3

3

5

5

12

3

3

5

5

12

5

5

3

3

Overall direction of replication

Primase

DNA Pol I

DNA Ligase

Page 22: Fig. 16-9-3

Fig. 16-17

OverviewOrigin of replication

Leading strand

Leading strand

Lagging strand

Lagging strandOverall directions of

replication

Leading strand

Lagging strand

Helicase

Parental DNA

DNA pol III

Primer Primase

DNA ligase

DNA pol III

DNA pol I

Single-strand binding protein

5

3

5

5

5

5

3

3

3

313 2

4

Page 23: Fig. 16-9-3

Figure 16.18

Parental DNA

DNA pol III

Leading strand

Connectingprotein

Helicase

Lagging strandDNA pol III

Laggingstrandtemplate

5

5

5

5

5

5

3 3

33

3

3

Page 24: Fig. 16-9-3

5’ ATGTCAAC 3’3’GACTACAGTTGACGTACG5’

In a test tube:DNA Pol III +

dNTPs +

Page 25: Fig. 16-9-3

5’ ATGTCAACTGCATGC3’3’GACTACAGTTGACGTACG5’

Why can’t dNTPs add to the 5’ end of the primer?

In a test tube:DNA Pol III +

dNTPs +

Page 26: Fig. 16-9-3

deoxynucleotide triphosphates (dNTPs)i.e. dATP, dGTP, dCTP, dTTP

The fundamental building blocks for DNA synthesis