本論文中我們將介紹一種新穎且便利的利用微波的固相多肽合成方法，以及在此方法協助下對一組混合肽之間相互作用的研究。與傳統的多肽合成相比，微波輻射幫助提高耦合過程的效率，從而大大縮短了合成時間，以及提高了反應效率。家庭用和實驗室用微波爐的比較表明，家用微波爐在實驗室條件下足以勝任微波輔助固相多肽合成。在第二部分，我們利用微波固相多肽合成合成了一組多肽用以探究其之間相互作用。一對在之前文獻報導的，通過庫篩選得到的結合肽被用來與另一組捲曲肽組合構成混合肽，期望得到強而且具特異性的相互作用以用作蛋白的標記。然而文獻報導的這對多肽並未達到預期的相互作用，因此我們需要在後續實驗中重新設計混合肽。 / This thesis summarizes an investigation into a novel solid-phase peptide synthesis protocol assisted by microwave irradiation, as well as an attempt to design hybrid peptides for enhanced binding properties. Compared with conventional peptide synthesis, a brief microwave irradiation during coupling and deprotection was shown to significantly reduce the time for peptide synthesis, at the same time yielding satisfactory product purity. A comparison of a domestic and a laboratory microwave oven indicated that the former could be easily adapted for conducting microwave-assisted solid phase peptide synthesis in a research laboratory, a facile and budget-efficient solution for enhanced efficiency in solid phase synthesis. In the second part of the research, we utilized the developed protocol to synthesize a set of peptides to investigate peptide-peptide interaction. A pair of binding peptides previously identified through library screening and genetic selection reported in literature was fused with designed coiled coil peptides to afford hybrid peptides, which was expected to result in exceptionally strong interaction and enhanced specificity. These hybrid peptide pairs could find applications in protein labeling, immunoblotting, and purification. However, the peptide pair did not demonstrate the claimed binding affinity in the literature. Therefore, the current design is flawed, and we shall re-design hybrid peptides based on other binding pairs in the following research. / Detailed summary in vernacular field only. / Zhang, Han. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Abstracts also in Chinese. / 摘要 --- p.I / ABSTRACT --- p.II / TABLE OF CONTENTS --- p.III / ACKNOWLEDGEMENT --- p.V / ABBREVIATION --- p.VI / Chapter Chapter 1 --- Microwave -assisted synthesis of a defensin peptide: a comparison of domestic and laboratory microwaves --- p.1 / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1. --- Defensins --- p.1 / Chapter 1.2. --- Solid-phase peptide synthesis (SPPS) --- p.5 / Chapter 1.3. --- Microwave (MW) heating in organic synthesis --- p.6 / Chapter 1.4. --- Microwave (MW) heating assisted solid phase peptide synthesis --- p.7 / Chapter 2. --- METHODS --- p.8 / Chapter 2.1. --- General synthetic approach of SPPS --- p.8 / Chapter 2.2. --- Microwave-assisted SPPS --- p.9 / Chapter 2.3. --- Analysis and characterization of the product --- p.12 / Chapter 3. --- RESULT AND DISCUSSION --- p.12 / Chapter 3.1. --- Exploring the coupling step under microwaving --- p.12 / Chapter 3.2. --- Nαdeprotection under microwave heating --- p.14 / Chapter 3.3. --- Synthesis of the target peptide --- p.16 / Chapter 3.4. --- SPPS in laboratory MW reactor --- p.18 / Chapter 3.5. --- SPPS by standard conventional method --- p.20 / Chapter 3.6. --- Comparison of the three methods --- p.21 / Chapter 3.6.1. --- Product p Product p urity --- p.21 / Chapter 3.6.2. --- Time and cost --- p.24 / Chapter 3.6.3 --- Sc alabiltiy of SPPS --- p.24 / Chapter 4. --- Exploration of the mechanism of microwave-assisted SPPS: thermal or nonthermal effect? --- p.25 / Chapter 5. --- CONCLUSION --- p.29 / REFERENCE --- p.30 / Chapter Chapter 2 --- Hybrid peptides with enhanced affinity and specificity for protein labeling --- p.33 / Chapter 1. --- INTRODUCTION --- p.33 / Chapter 1.1. --- Protein labeling --- p.33 / Chapter 1.2. --- Hybrid peptides sequences --- p.35 / Chapter 2. --- EXPERIMENTAL SECTION --- p.36 / Chapter 2.1. --- HPLC result --- p.37 / REFERENCE --- p.48

by Marco Ming Yeung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 90-96). / ACKNOWLEDGMENTS --- p.i / ABSTRACT --- p.ii / CONTENTS --- p.iii / LIST OF FIGURES --- p.v / LIST OF TABLES --- p.vi / ABBREVIATIONS --- p.vii / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1. --- Theoretical Background of Nonlinear Optics --- p.1 / Chapter 1.2. --- Organic Nonlinear Optical Chromophores --- p.5 / Chapter 1.3. --- Porphyrins as Nonlinear Optical Chromophores --- p.8 / Chapter 1.4. --- Synthetic Aspects of Porphyrins --- p.16 / Chapter 1.4.1. --- Porphyrin Substrates --- p.16 / Chapter 1.4.2. --- Vilsmeier Formylation --- p.17 / Chapter 1.4.3. --- Bromination --- p.21 / Chapter 1.4.4. --- Knoevenagel Condensation --- p.24 / Chapter 1.4.5. --- Palladium-mediated Cross-coupling --- p.25 / Chapter 2. --- RESULTS AND DISCUSSION --- p.28 / Chapter 2.1. --- "Preparation of 5,15-Diphenylporphyrinatonickel(II)" --- p.28 / Chapter 2.2. --- "Vilsmeier Formylation of 5,15-Diphenylporphyrinatonickel(II)" --- p.30 / Chapter 2.3. --- Preparation of Push-pull Porphyrins --- p.47 / Chapter 2.4. --- Molecular Structures of 65 and76 --- p.59 / Chapter 2.5. --- Nonlinear Optical Properties of Push-pull Porphyrins 65 and66 --- p.63 / Chapter 2.6. --- Attempted Syntheses of Push-pull Porphyrin Trimer and Dimer --- p.65 / Chapter 2.7. --- Conclusion --- p.69 / Chapter 3. --- EXPERIMENTAL SECTION --- p.70 / Chapter 3.1. --- General Methods --- p.70 / Chapter 3.2. --- Physical Measurements --- p.70 / Chapter 3.3. --- Preparation of Push-pull Porphyrins --- p.71 / Chapter 3.4. --- Attempted Preparation of Push-pull Porphyrin Trimer and Dimer --- p.86 / Chapter 4. --- REFERENCES --- p.90 / APPENDIX A 1 H NMR Spectra of Porphyrins --- p.97 / APPENDIX B Crystal Data for 65 and 76 --- p.115 / APPENDIX C Computed Geometry of 65 and 66 from Semiempirical PM3(tm) Calculations --- p.131

本文描述了碳環核苷的發展過程，同時也描述了將不同環融合在五元碳環上的方法來對碳環核苷的構象進行鎖定。 / 以D-核糖為起始原料，經過12 步反應並以分子內的Diels-Alder 反應 (IMDA)為關鍵步驟合成出了關鍵的中間體192，它的總產率為27%。通過對中間體192中的環己烯的結構進行修飾，經過3-4 步反應成功合成出了7 個具有雙環[4.3.0]壬烷結構的碳環核苷（185-191），它們的構型也通過其X 光單晶結構圖來進行確定。[附圖] / 以一價銅催化端炔和疊氮化物的Huisgen 環加成反應為關鍵步驟，成功地合成出了12 個具有雙環[4.3.0]壬烷結構的碳環三唑核苷。[附圖] / 同時，我們也合成12 個具有雙環[4.3.0]壬烷結構的碳環三唑核苷羧酸。[附圖] / 另外，我們也合成出了两個在三唑環上含有羧酸的碳環三唑核苷（298 和 299）。[附圖] / 最後，我們還合成出了16 個含有大基團叔丁基羧酸酯的碳環三唑核苷(260-263, 273-276, 286-289 和294-297)。[附圖] / In this thesis, a review regarding the development of carbobicyclic nucleosides and conformationally locked carbobicyclic nucleosides by fusing different rings onto the five-member ring was presented. / The key intermediate 192 was synthesized from D-ribose in 12 steps with 27% overall yield, using an Intramolecular Diels-Alder reaction (IMDA) as the key step. By modification of the cyclohexene ring, seven carbobicyclic adenosine analogues 185-191 with a bicyclo[4.3.0]nonane framework were prepared successfully from intermediate 192 in 3 to 4 steps and their conformations were examined by X-ray crystallography [with diagram]. / Twelve carbobicyclic ribavirin analogues 232-239 and 250-253 with a bicyclo[4.3.0]nonane framework were synthesized successfully by using a copper catalyzed azide-alkyne cycloaddition (Huigsen reaction) as the key step [with diagram]. / Another twelve ribavirin analogues bearing a carboxylate group (264-267, 277-280 and 290-293) with a bicyclo[4.3.0]nonane framework were also obtained [with diagram]. / Furthermore, two more ribavirin analogues bearing a carboxylic acid in triazole (298 and 299) with a bicyclo[4.3.0]nonane framework were obtained. [with diagram] / Finally, twelve ribavirin analogues bearing a tert-butyl carboxylate ester (260-263, 273-276, 286-289 and 290-293) with a bicyclo[4.3.0]nonane framework were also obtained [with diagram]. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Li, Fanglin. / Thesis (Ph.D.) Chinese University of Hong Kong, 2015. / Includes bibliographical references (leaves 175-187). / Abstracts also in Chinese.

The faithful replication of DNA depends on the appropriate balance of DNA precursors. From studies conducted in bacteriophage T4, models for deoxyribonucleotide biosynthesis producing pools appropriate for DNA replication have made it possible to understand more complex systems. A portion of that body of evidence supports the concept that deoxyribonucleotide biosynthesis for bacteriophage T4 is carried out by an association of enzymes and other cellular components in a complex called the dNTP synthetase complex. This dissertation explores potential direct protein-protein interactions within this complex for the preparation of pyrimidine deoxyribonucleotides. Direct associations for enzymes involved in pyrimidine deoxyribonucleotide biosynthesis were examined by affinity chromatography. It was determined that there was a significant direct relationship between T4 thymidylate synthase and T4 dCMP deaminase, between T4 dCTPase/dUTPase and T4 dCMP deaminase as well. The interaction between thymidylate synthase and dCMP deaminase was significantly influenced by the presence of dCTP, a positive effector of dCMP deaminase. Furthermore, protein associations changed the kinetic character of pyrimidine deoxyribonucleotide production. T4 dCTPase/dUTPase, a member of the dNTP synthetase complex, significantly alters the kinetic nature of thymidylate synthase by working with thymidylate synthase in a reciprocal relationship. T4 single-stranded DNA binding protein, a member of the replication complex, alters the activity of thymidylate synthase as well. Attempts to isolate a kinetically coupled complex from two or more constituent proteins of the dNTP synthetase complex were frustrated by protein degradation to fragments under 10 kDa in size. Pyrimidine deoxyribonucleotide synthesis is located between the significant energy investment of ribonucleotide reductase and phosphate attachments by kinases to prepare the deoxyribonucleotide molecules for DNA replication. In bacteriophage T4, intermediate reactions are driven by mass action but are modulated by subtleties including direct protein associations and the presence of small molecules that influence enzyme function. Through these and potentially similar controls, pools of deoxyribonucleotides are prepared and delivered in a timely, balanced manner to the DNA replication apparatus. / Graduation date: 2002

Graduation date: 1999

Graduation date: 2003

Graduation date: 1999

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