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、 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、 the linkage ----

phosphodiester bridge

3’terminal

5’terminal

Nucleotide residues

三、 the primary structure of nucleic

acid definition

writing method

polinucleotide

oligonucleotide

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

3.the force maintaining the

double helix stability

* hydrogen bond

* Stacking force

4. Some difference steric

conformation types of DNA double helix

A 型 B 型 Z 型结晶湿度 75% 92% 高盐溶液结

晶 方向

直径

螺距

螺旋一周所含

碱基

右手 右手 左手

表面只有一大沟碱基为嘌啉呤，嘧啶交替，

2.55nm

2.46nm 3.4nm

0.23nm 0.34nm相邻碱基距离

11 10 12

2nm

5. The tertiary structure

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、 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 ψC arm TψC 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

(7mG5’ppp5’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

prokaryotes eukaryotes 5s,23s 5s,5.8s,28sLarge 50s 60sSubunit 34rP 49rP

Small 16s 18s subunit 30s 40s 21rP 33 rPTotal size 70s 80s

diameter 8nm diameyer 23nm

Shine-dalgarno sequence in

16s RNA (initiation sequence of protein synthesis in prokaryotes

conservation sequences of 5sRNA and 5.8sRNA can recognise TψC 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