Metabolism of nucleic acids the structure & functionlibvolume1.xyz/.../nucleicacidmetabolismpresentation2.pdfThe structure of nucleic acids 1.summarize the discovery The function The

Metabolism of nucleic acids

the structure & function

The structure of nucleic acids

1.summarize

the discovery

The function

The headway

A. nucleotides

base（（（（purine、、、、pyrimdine））））+ribose（（（（deoxyribos

N-glycosyl linkage

nucleoside+phosphate

phosphoester linkage

nucleotide

phosphodiester linkage

nucleic acid

B. The structure of the

nucieic acid

一一一一、、、、the building block molecule of

nucleic acid--nucleotide

In RNA:

AMP、、、、CMP、、、、GMP、、、、TMP

In DNA:

dAMP、、、、dCMP、、、、dGMP 、、、、dUMP

The physiological function

of the nucleotides

二二二二、、、、the linkage ----

phosphodiester bridge

3’’’’terminal

5’terminal

Nucleotide residues

三三三三、、、、the primary structure of nucleic

acid

definition

writing method

polinucleotide

oligonucleotide

四四四四、、、、the structure of DNA

* concept

1.the primary structure of DNA

* writing method

5’’’’-AATTCGGATCTTAGC-3’

* characteristics

specificity in race

non specificity in tissues

Chargff Law

2.the secondary structure of DNA

Watson-Crick double helix

structure

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3.the force maintaining the

double helix stability

* hydrogen bond

* Stacking force

4. 4. 4. 4. Some difference Some difference Some difference Some difference steric steric steric steric

conformation types conformation types conformation types conformation types of DNA double helixof DNA double helixof DNA double helixof DNA double helix

A型型型型 B型型型型 Z型型型型

结晶湿度结晶湿度结晶湿度结晶湿度 75% 92% 高盐溶液结晶高盐溶液结晶高盐溶液结晶高盐溶液结晶

方向方向方向方向

直径直径直径直径

螺距螺距螺距螺距

螺旋一周所含螺旋一周所含螺旋一周所含螺旋一周所含

碱基碱基碱基碱基

右手右手右手右手 右手右手右手右手

左手左手左手左手

表面只有一大表面只有一大表面只有一大表面只有一大沟碱基为嘌啉沟碱基为嘌啉沟碱基为嘌啉沟碱基为嘌啉呤呤呤呤，，，，嘧啶交替嘧啶交替嘧啶交替嘧啶交替，，，，

2.55nm

2.46nm 3.4nm

0.23nm 0.34nm 相邻碱基距离相邻碱基距离相邻碱基距离相邻碱基距离

11 10 12

2nm

5. 5. 5. 5. The tertiary structureThe tertiary structureThe tertiary structureThe tertiary structure

of nucleic acid of nucleic acid of nucleic acid of nucleic acid

The length of genome DNA

6106Kb

DNA supercoiling

The basic structure of

chromosome --- nucleosome

Nucleosome

（（（（ DNA double helix of containing 200bp ））））

140bp DNA double

helix

histone

(H2A1)2,(H2B)2,(H3)2,(H4)2，，，，octamer

Core particles

60bp DNAdouble helix fragment+H1histone（（（（linkage region））））

Core particles

a string of beads of nucleosome

further fold to form chromosome

五五五五、、、、the structure of RNA

1.summarize

• Content

• components & linkage

• inhomogeneity

• steric conformation

• function

2. The structure of tRNA

* kinds

* commonness

(1) The primary structure

of tRNA

* 5’’’’ PG, 3’ CCA

* more rare bases

(2) The secondary structure

of tRNA

Characteristic structure

*Amino acid arm

* DHU arm DHU ring

* T ψCCCC arm TψCCCC ring

•Anticodon arm anticodon ring

extra fork

(3) The tertiary structure

of tRNA

twisted L

3. The structure of mRNA

(1) Summarize

* characteristic

Prokaryotes --polycistronic

Eukaryotes-- monocistronic

(2) The characteristic of

Prokaryotes mRNA

(3) The characteristic of

eukaryotes mRNA

Heterogeneous nuclear

RNA, hnRNA

• Concept

• characteristic

The structure of 5’ Cap

((((7777mmmmG5G5G5G5’ppp5ppp5ppp5ppp5’Np)Np)Np)Np)

The function of 5’cap

The structure of 3’ tail

( Poly A)

The function of 3’ tail

4. The structure of rRNA

(1) Summarize

prokaryotes eukaryotes

Type 5s, 16s,23s 5s,5.8s,18s,28s

The number 120 ,1542 ,3200 120,160,1940,4718

of nucleotides

proproproprokaryotes eukaryotes 5555s,23s 5s,5.8s,28ss,23s 5s,5.8s,28ss,23s 5s,5.8s,28ss,23s 5s,5.8s,28s

Large 50s 60sLarge 50s 60sLarge 50s 60sLarge 50s 60s

Subunit 34rP 49rPSubunit 34rP 49rPSubunit 34rP 49rPSubunit 34rP 49rP

Small 16s 18s Small 16s 18s Small 16s 18s Small 16s 18s

subunit 30s 40ssubunit 30s 40ssubunit 30s 40ssubunit 30s 40s

21rP 33 rP21rP 33 rP21rP 33 rP21rP 33 rP

TotalTotalTotalTotal sizesizesizesize 70707070ssss 80808080ssss

diameterdiameterdiameterdiameter 8888nmnmnmnm diameyerdiameyerdiameyerdiameyer 23232323nmnmnmnm

Shine-dalgarno sequence in

16s RNA (initiation sequence of

protein synthesis in prokaryotes

conservation sequences of

5sRNA and 5.8sRNA can

recognise TψCCCC ring in tRNA

The physic-chemical

propertices of nucleic acids

1. size

2. Hydrolysis of nucleic acids

3.denaturation,renaturation,

hybridization

a. denaturation,

*concept

* hyperchromic effect

mechanism

* melting curve

• melting temperature (Tm)

Concept

characteristics

b. Renaturation (annealing)

Concept

characteristics

hypochromic effect

mechanism

c. Hybridization

concept

Gene & genome

• Concept of gene

• classification of gene

• concept of genome

• gene family

• split gene

• pseudogene