中南大学 生物化学 考研课件 ch11 核苷酸和核酸 nucleic acids.ppt

Biochemistry,For Specialty of Biotechnology or Bioengineering at CSU Mr. XIA Jinlan,Chapter 11 Nucleotides and Nucleic acids 核苷酸和核酸,Information transfer in a cell细胞中信息的转化 The bases, nucleoside and Nucleotide 碱基、核苷、核苷酸 Basic Structure of nucleic acids 核酸结构 Classes of nucleic acids 核酸的类型 Hydrolyses of nucleic acids 核酸的水解,Information transfer in a cell细胞中信息的转化,DNA is transforming material （DNA 是转化物质） Information flow and Central dogma信息流与中心法则,DNA is transforming material （DNA 是转化物质）,Griffths transforming experiments (1928) showed some materials inside the S strain had transferred to Live R strain 证明细胞内物质能在细胞间转化,O T Avery testified the transforming substance was DNA (1944) 证明转化物质是DNA,A Hershey and M Chase further testified transforming substance was DNA by infection of bacteria with T2 (1952) 进一步通过噬菌体T2 对细菌感染的试验证明转化物质是DNA,Question: Please point out the biomolecules that are related to the information flow.请指出与信息流相关的生物分子,Information flow信息流,mRNA,Protein,Transcription 转录,Reverse transcription 反转录,Translation 翻译,Central dogma 中心法则,The bases, nucleoside and Nucleotide （碱基、核苷、核苷酸）,Nucleoside=base-sugar The two types of common bases The two types of common sugars Nucleotide = Nucleoside-phosphate Structure of a representative nucleotide 代表性核苷酸结构 Names of common bases, nucleosides and nucleotides 常见碱基，核苷和核苷酸名称 High energy Phosophoester bonds 高能磷酯键 Other important forms of nucleotides其它重要核苷酸类型,Two types of bases in nucleic acids,Pyrimidine 嘧啶,Purine嘌呤,Uracil 尿嘧啶,Thymine 胸腺嘧啶,Cytosine 胞嘧啶,Guanine 鸟嘌呤,Adenine 腺嘌呤,(only in RNA),(only in DNA),In both DNA and RNA,Two types of sugars in nucleic acids,D-Ribose,D-2-Deoxyribose,(only in RNA),(only in DNA),Structure of a representative nucleotide 代表性核苷酸结构,e.g., Adenine 腺嘌呤, Adenosine 腺苷, Adenosine phosphate 腺苷酸,Base: adenine,Nucleoside: adenosine,Nucleotide,Adenosine 5-monophosphate,Adenosine 5-diphosphate,Adenosine 5-triphosphate,Names of common bases, nucleosides and nucleotides 常见碱基，核苷和核苷酸,ADP (adenosine 5-diphosphate),ATP (adenosine 5-triphosphate),The high energy phosophoester bonds,Examples,Other important forms of nucleotides,Basic Structure of nucleic acids 核酸基本结构,Nucleotides bind together by 3 5-phosphodiester bonds 5 end: phosphate 3 end: hydroxyl group Nucleic acids or polynucleotides are written as base sequences 核酸或多核苷酸的书写方式是碱基序列 Nucleic acids or polynucleotides are also expressed by schematical mode 核酸也可以图解方式表示,Structure of nucleic acids 核酸结构,Binding together by 3 5-phosphodiester bonds 5 end: phosphate 3 end: hydroxyl group,Take DNA as an example,Comparison of chain structure between RNA and DNA,Written forms of Nucleic acids or polynucleotides 核酸或多核苷酸的书写方式,Simply list the single capital letters of bases e.g., GACTGUA With p to indicate the phosphodiester bridge用磷（酸根）指出磷二酯键 GpApCpTpGpUpAp (3-OH end) pGpApCpTpGpUpA (5-OH end),Schematical expressing mode of nucleic acids 核酸图解表示方式,Or simply,Classes or nucleic acids 核酸的类型,DNA RNA mRNA (messenger ) tRNA (transfer ) rRNA (ribosome ) snRNA (small nuclear , only in Eucaryotic cells),Problem for self-study: Where are the locations of the different classes of nucleic acids in a procaryotic or eucaryotic cell, respectively, and what are their functions?,Hydrolysis of nucleic acids 核酸水解,Hydrolysis by acid or base 酸或碱性水解 Randomly 随机（水解） DNA is acidic labile, e.g., be hydrolysed the purine glycosidic bonds by 1mM HCl （DNA易于被稀酸水解） RNA is alkali labile, e.g., hydrolyzed by dilute NaOH（RNA易于被稀碱水解） Enzymatic hydrolysis Specifically 特异性地水解 Nuclease specificity核酶特异性 RNases, DNases or nucleases (both for DNA and RNA) Exonucleases 外切核酸（水解）酶 Endonucleases 内切核酸（水解）酶 Restriction enzymes 限制性（水解）酶,(see table 11.4, p349),2-OH in ribose of RNA is susceptible to nucleo- philic attack on 3-phosphodiester （RNA中核糖