1、BiochemistryFor Specialty of Biotechnology or Bioengineering at CSUMr.XIA JinlanChapter 11 Nucleotides and Nucleic acids 核苷酸和核酸核苷酸和核酸nInformation transfer in a cell细胞中信息的转化nThe bases,nucleoside and Nucleotide 碱基、核苷、核苷酸 nBasic Structure of nucleic acids 核酸结构nClasses of nucleic acids 核酸的类型nHydrolyses
2、of nucleic acids 核酸的水解Information transfer in a cell细胞中信细胞中信息的转化息的转化nDNA is transforming material（DNA 是转化物质）nInformation flow and Central dogma信息流与中心法则DNA is transforming material（DNA 是转化物质）是转化物质）nGriffths transforming experiments(1928)showed some materials inside the S strain had transferred to Liv
3、e R strain 证明细胞内物质能在细胞间转化nO T Avery testified the transforming substance was DNA(1944)证明转化物质是DNA nA Hershey and M Chase further testified transforming substance was DNA by infection of bacteria with T2(1952)进一步通过噬菌体进一步通过噬菌体T2 对细菌感染的对细菌感染的试验证明转化物质试验证明转化物质是是DNAQuestion:Please point out the biomolecule
4、sthat are related to the information flow.请指出与信息流相关的生物分子Informationflow信息流信息流mRNAProteinTranscription转录转录Reverse transcription反转录反转录Translation翻译翻译Gene expression基因表达基因表达Central dogma 中心法则中心法则DNAThe bases,nucleoside and Nucleotide（碱基、核苷、核苷酸）碱基、核苷、核苷酸）nNucleoside=base-sugarnThe two types of common ba
5、sesnThe two types of common sugarsnNucleotide=Nucleoside-phosphatenStructure of a representative nucleotide 代表性核苷酸结构nNames of common bases,nucleosides and nucleotides 常见碱基，核苷和核苷酸名称nHigh energy Phosophoester bonds 高能磷酯键nOther important forms of nucleotides其它重其它重要核苷酸类型要核苷酸类型Two types of bases in nucle
6、ic acidsPyrimidine 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 inRNA)(only inDNA)In both DNA and RNATwo types of sugars in nucleic acidsD-RiboseD-2-Deoxyribose(only in RNA)(only in DNA)Structure of a representative nucleotide代表性核苷酸结构代表性核苷酸结构e.g.,Adenine 腺嘌呤,Adenosine 腺苷,Adenos
7、ine phosphate 腺苷酸Base:adenineNucleoside:adenosineNucleotideAdenosine 5-monophosphateAdenosine 5-diphosphateAdenosine 5-triphosphateNames of common bases,nucleosides and nucleotides 常见碱基，核苷和核苷酸Base 碱基碱基Nucleoside 核苷核苷Nucleotide核苷酸核苷酸basePurines Adenine,AGuanine,Gbase-(deoxy)ribose(deoxy)Adenosine(deo
8、xy)Guanosinebase-(deoxy)ribose-phosphate(d)ATP,(d)ADP,(d)AMP(d)GTP,(d)GDP,(d)GMPPyrimidinesThymine,TCytosine,C(deoxy)Thymidine(deoxy)Cytidine(d)TTP,(d)TDP,(d)TMP(d)CTP,(d)CDP,(d)CMPADP(adenosine 5-diphosphate)ATP(adenosine 5-triphosphate)The high energy phosophoester bondsExamples Other important fo
9、rms of nucleotidesBasic Structure of nucleic acids 核酸基本结构核酸基本结构nNucleotides bind together by 3 5-phosphodiester bondsn5 end:phosphaten3 end:hydroxyl groupnNucleic 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nNucleic acids or polynucleotides are also expressed by schematic
10、al mode 核酸也可以图解方式表示Structure of nucleic acids 核酸结构核酸结构nBinding together by 3 5-phosphodiester bondsn5 end:phosphaten3 end:hydroxyl groupOCH2OPO-OOPO-OOCH2BaseHHHHHOOPO-OOCH2BaseHHHHHOOHBaseHHHH33355553Take DNA as anexampleComparison of chain structure between RNA and DNAWritten forms of Nucleic acid
11、s or polynucleotides 核酸或多核苷酸的书写方式核酸或多核苷酸的书写方式nSimply list the single capital letters of basesne.g.,GACTGUAnWith p to indicate the phosphodiester bridge用磷（酸根）指出磷二酯键nGpApCpTpGpUpAp (3-OH end)npGpApCpTpGpUpA(5-OH end)Schematical expressing mode of nucleic acids 核酸图解表示方式核酸图解表示方式Or simplyClasses or nucle
12、ic acids 核酸的类型核酸的类型nDNAnRNAnmRNA(messenger)ntRNA(transfer)nrRNA(ribosome)nsnRNA(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
13、nucleic acids 核酸水解核酸水解nHydrolysis by acid or base 酸或碱性水解nRandomly 随机（水解）nDNA is acidic labile,e.g.,be hydrolysed the purine glycosidic bonds by 1mM HCl（DNA易于被稀酸水解）nRNA is alkali labile,e.g.,hydrolyzed by dilute NaOH（RNA易于被稀碱水解）nEnzymatic hydrolysisnSpecifically 特异性地水解nNuclease specificity核酶特异性nRNase
14、s,DNases or nucleases(both for DNA and RNA)nExonucleases 外切核酸（水解）酶nEndonucleases 内切核酸（水解）酶nRestriction 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中核糖中核糖2-OH在碱性条件下，易于亲核进攻在碱性条件下，易于亲核进攻3-磷酸二酯键）磷酸二酯键）More see Fig 11.29,p346 or Enzymatic cleavage in polynucleotide chainsExamples for“a”or“b”specific exonuclease脾磷二酯酶蛇毒液磷二酯酶Homework pp354-355Problems 1,3,4,6
