Characterization for Interaction of Antitumor-active Metal Complexes with Oligonucleotide by Electroespray Ionization Mass Spectrometry
| Autor: | Hsin-I Tang, 湯欣儀 |
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| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 The gentle nature of the ESI proess, however, means that ESI-MS is also finding application for the study of noncovalent and other fragile biomolecular complexes. The thesis included three section: First section: Determination of Binding Location Preference between Short Oligonucleotide and Ru-complexes Analyzed by Ion Trap Mass Spectrometry The interaction of two ruthenium (II) complexes, [Ru(terpy)(bpy)Cl]Cl and cis-[Ru(bpy)]Cl2, with single-stranded DNA wereinvestigated by electrospry ionization mass spectrometry. The DNA binding sits preference of [Ru(terpy)(bpy)Cl]Cl and cis-[Ru(bpy)]Cl2 were located at central guanine, which was determined by tandem mass spectrometry technique. The Ru-complexes bounds to guanine also enhanced the loss of guanine-Ru, and gave a-B and w fragments. Second section: Factors Influence on Gas-Phase Stability of Double Stranded Oligonucletoides Studied by Electrospray Mass Spectrometry The topic studied in relativity between gas-phase stability of double stranded oligonucletides and experimental system. According to this experimental results: the experimental system was set up at capillary temperature at 120-140℃; adding concentration of NH4OAc is 200-500 times over concentration of oligonucletides; the volatile solvent- isopropanol have been used as and the compositions again water 75%. Third stction: Kinetic of the DNA binding Azole-Bridged Dinuclear Platinum(II) compounds by Electrospray ionization Mass Spectrometry The kinetics of the reaction between three new derivatives of azole-bridged dinuclear platinum (Ⅱ) complex, (1), [{cis-Pt(NH3)2}2(μ-OH)-(μ-pyrazolate)][NO3]2 (2), [{cis-Pt(NH3)2}2(μ-OH)-(μ-1,2,3-triazolate)][NO3]2 and (3), [{cis-Pt(NH3)2}2(μ-OH)-(μ-phenyltriazolate)][NO3]2 and complementary double-stranded DNA was investigated by electrospray ionization mass spectrometry. Products with different binding modes were observed and shows competition at different time intervals. Ionic/electrostatic binding products dominate at early stage of reaction and gradually transform into covalently modified adduct by removal of hydroxyl leaving group. We proposed that the binding of the dinuclear platinum complexes to the double-stranded nucleic acids may be considered as a three-step process: rapid initial electrostatic binding followed by covalent attachment of the drug by sequential displacement of the leaving group to the N7 position of guanosines, giving first monofunctional and subsequently bifunctional adducts. The binding affinity of three derivatives to complementary 12-mer oligonucleotides are in the order of 3>1»2, which are determined by the ratio of intensity of electrostatic adduct to that of unbound free DNA. On the hand, comparison of the relative intensities of mono- and difunctional platinum covalent adduct suggested that the reactivity for these Pt(Ⅱ) complexes are in the order 2 > 1 > 3, parallel to the trend of cytotoxicity. Compared to other technique, the study shows that ESI is a sensitive and fast tool for confirmation of binding and determination of stoichometry for both covalent and noncovalent systems. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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