生物化学精品教学（河南科技大学）核酸.pptVIP

一、 History of Development of Research about Nucleic Acids 1868, Fridrich Miescher isolated “Nuclide” from pyocytes 1944,Avery confirmed DNA is genetic substances 1953,Watson Crick found the double helix structure of DNA 1968,Nirenberg broke down genetic code 1975,Temin Baltimore found reverse transcription enzyme 1981,Gilbert Sanger set up DNA-sequencing methods 1985,Mullis invented PCR technique 1990, United Stats started up human genome project (HGP） 1994, China joined in HGP 4. Important Free Nucleotides Their Ramification Bioactive compounds containing NTs： NAD+、NADP+、CoA-SH、FAD containing AMP Content Primary Structure of NA Steric Structure and Function of DNA * Secondary Structure of DNA ----- Double Helix * Tertiary Structure of DNA * Function of DNA Steric Structure Function of RNA 一、Primary Structure Definition： The sequence of arrangement of nucleotides in Nucleic Acids. Because nucleic acids differ one from another by the sequence of the bases, so that the primary structure was also called as bases sequence. 三、Function of DNA The Principle function is as a templet based on which genes are expressed and genetic information are replicated. DNA is substantial foundation of heredity and reproduction of life, and that of life activity of individual organism. 3.1 Characteristic of primary structure: Containing 10～20% rare bases,such as DHU… 3’-end has CCA-OH sequence 5’-end containing many base “G” Having T?C 1.1 Acidic –Basic Scales Solubility of DNA DNA is amphoteric macromolecules containing phosphoric acid radical basic groups,but has slightly acidic value. React with metal ions to form salts, but not dissolve in ethanol or isopropanol 1.2 High-Molecule Nature of DNA Viscosity： DNARNA dsDNA ssDNA Sedimentation behavior 1.3 Ultraviolet absorption of DNA OD260nm Minonucleotidt ssDNA dsDNA 2.5 Heating denaturation Meltin Curve: Temperature-OD260nmrelati