河南农业大学：《生物化学》课程PPT教学课件（本科双语教学）第七章 核酸的生物合成 Structure of Nucleic Acids

Chapter 7 Structure of Nucleic Acids 司形行感H之 "Scherzo in D E"(detail)by David E.Rodale 1955-1985)

Chapter 7 Structure of Nucleic Acids "Scherzo in D & E" (detail) by David E. Rodale (1955-1985)

RNA 7.1·The Primary Structure of Nucleic Acids

7.1 · The Primary Structure of Nucleic Acids

Structure and Nomenclature of Nucleic Acids NH2 N Shorthand notation N of a nucleic acid 0 ①aQCC3 NH RRROH NH2 5 Two major classes of nucleic acids: DNA and RNA

Structure and Nomenclature of Nucleic Acids N N N N NH2 O O OH H H H H O P O O O- NH N N O NH2 N O OH H H H H O O P -O O- 5’ 3’ P P T P A P G P C OH C 5’ 3’ Shorthand notation of a nucleic acid Two major classes of nucleic acids: DNA and RNA

Sequencing Nucleic Acids 1 chain termination or dideoxy method 2 base-specific chemical cleavage method

Sequencing Nucleic Acids 1 chain termination or dideoxy method 2 base-specific chemical cleavage method

DNA sequencing The Sanger DNA sequencing method uses dideoxy nucleotidcs to terminate DNA synthesis, yielding a series of DNA fragments whose sizes can be measured by electrophoresis.The last base in each of these fragments is known,because we know which dideoxy nucleotide was used to terminate each reaction.Therefore,ordering these fragments by size-each fragment one (known) base longer than the next-tells us the base sequence of the DNA

DNA sequencing The Sanger DNA sequencing method uses dideoxy nucleotidcs to terminate DNA synthesis, yielding a series of DNA fragments whose sizes can be measured by electrophoresis. The last base in each of these fragments is known, because we know which dideoxy nucleotide was used to terminate each reaction. Therefore, ordering these fragments by size-each fragment one (known) base longer than the next-tells us the base sequence of the DNA

(a)Primer extension reaction: TACTATGCCAGA- 21-base primer Replication with ddTTP TACTATGCCAGA (26 bases) ATGAD

(b)Products of the four reactions: Products of ddA rxn Products of ddC rxn Template:. TACTATGCCAGA_ Template: TACTATGCCAGA_ (22) 0 (28) ATGATA (25) ATGA 32) (27） ATGATACGGTO ATGATA

Products of ddG rxn Products of ddT rxn Template: TACTATGCCAGA_ Template: TACTATGCCAGA (24) ATO (23) AD 29) ATGATAC (26) ATGAD (30) ATGATACG 31) ATGATACGGO 33) ATGATACGGTCO

(c)Electrophoresis of the products: ddA ddC ddG ddT 一 T OH 二 G G 一 A G A

ACGT Figure 5.19 A typical sequencing film.The sequence begins CAAAAAACGG.You can probably read the rest of the sequence to the top of the film.(Source:Courtesy Life Technologies,Inc.,Gaithersburg.MD.)