Chapt DNA Replication 1 1 Semiconservation replication 5

Chapt. DNA Replication 1. 특징 1) Semiconservation replication 5’ 5’ 3’ 3’ + 3’ 5’ 2) 5’ → 3’ 방향 DNA 합성(복제시작 점에서 양쪽 방향) 3) leading strand ; 연속합성 lagging strand ; 불연속합성 4) RNA primer 필요 ss DNA 3’ 5’RNA primer 3’ 5’ 5’ 3’ RNA DNA BIOPARK

• Semiconservation replication

2. Replication에 관여하는 Enzymes and Proteins 1) Helicase ; ds – DNA → ss – DNA로 풀어주는 효소 (Dna. B) Primosome ex) SV 40 Tag (Simian Virus) Figure The unwinding events in a replication fork. 2) Primase ; RNA primer의 5’ → 3’의 합성 (Dna. G): RNA polymerase BIOPARK

X-Ray structure of T 7 helicase.

3) Topoisomerase ; DNA super coiling을 풀어줌 ex) Topoisomerase III (E. coli DNA gyrase) ; Type IA Topoisomerase I (human) ; Type IB Topoisomerase II (yeast) ; Type II BIOPARK

4) DNA polymerase ; DNA 합성 d d ATP GTP CTP TTP DNA template Mg 2+ DNA ex) E. coli Polymerase I (928잔기, 324 -928(3’-5’Exo. ) 1 -323(5’-3’Exo. ) Polymerase III → DNA Polymerase BIOPARK

c). 5’ → 3’ 분해 (only polymerase I) BIOPARK

X-Ray structure of E. coli DNA polymerase I Klenow fragment in complex with a double-helix DNA. (3’-5’ Exonuclease)

X-Ray structure of Klentaq 1 in complex with DNA and with dd. CTP.

X-Ray structure of Klentaq 1 in complex with DNA and without dd. CTP.

5) Single – Strand DNA – binding Protein (SSB) = Human replication protein A (RPA) → DNA Replication, Repair, Recombinant에 관여 BIOPARK

X-Ray structure of SSB in complex with d. C(p. C)34.

6) DNA ligase → 3’ – OH + 5’ 말단에 연결 (Phosphodiester 결합 연결) BIOPARK

The reactions catalyzed by E. coli DNA ligase.

7) Okazaki fragment (lagging strand) → 증명 • Pulse – labeling experiment ( Fig. (b) top ) • Pulse – chase ( Fig. (b) bottom) BIOPARK

3. Complete DNA replication system 1) Initiation of DNA replication ⓐ origin of replication (ori) BIOPARK

ⓒ ori C + protein Dna A A+T 9 mers rich region 2) DNA 복제의 개요(Fig. 24 -15) BIOPARK

Key to Function. The replication of E. coli DNA.

X-Ray structure of the B clamp of E. coli Pol III holoenzyme.

Map of the E. coli chromosome showing the positions of the Ter sites.

D – loop (both direction) BIOPARK

The autoradiographic differentiation of unidirectional and bidirectional Q replication of DNA

X-Ray structure of E. coli Tus in complex with a 15 -bp Ter-containing DNA.

X-ray structure of PCNA.

Reverse Transcriptase

Electron micrograph of a fragment of replicating Drosophila DNA.

Removal of RNA primers in eukaryotes.

Replication of a linear chromosome.

Mechanism for the synthesis of telomeric DNA by Tetrahymena telomerase.

Structure of the telomeric oligonucleotide d(GGGGTTTTGGGG).

Electron micrograph of a T-loop.