大腸桿菌Thioredoxin活性區域突變株對噬菌體感染之影響

Abstract

中文摘要 Thioredoxin是一個小型且普遍存在於細菌至所有動植物的細胞的熱穩定性蛋白質。在E.coli中參與生理上的氧化還原反應，促進去氧核糖核酸的形成，也可幫助T7、f1、M13的生長。在噬菌體T7中，thioredoxin為T7 DNA polymerase的次單元；在線形噬菌體f1、M13參與噬菌體組裝的過程。本實驗中，我們在thioredoxin W31、G33、P34、C35、K36、M37位置建構了19株E.coli thioredoxin突變株，分析它們對噬菌體T3/T7、f1、M13、T7生長的影響。 由本實驗的各E.coli thioredoxin突變株的感染平盤效率(E.O.P值)得知P34D、P34E、P34K、C35A在37℃及42℃時嚴重抑制f1、M13、T3/T7的生長。另外K36R在42℃時，會促進f1、M13的生長。由T3/T7、f1、M13的實驗數據比較得知W31、P34、C35、K36應該是thioredoxin蛋白與f1 gene I蛋白交互作用時重要的接觸點。 i

Effects of active site Mutations of Escherichia coli Thioredoxin on Bacteriophage Infection Student：Pin-Wei Tseng Advisor: Dr. Tiao-Yin Lin Institute of Biological Science and Technology National Chiao Tung University Abstract Thioredoxin is a small heat stable protein that exists generally in bacteria to all animal and plant cells. In E.coli, it participates in physiologically oxidation-reduction reaction to form deoxyribonucleic acid as well as supports f1、M13 and T3/T7 growth. In phage T7, thioredoxin is a T7 DNA polymerase subunit. For phage f1 and M13, it participates in the assembly of filamentous phage. In this study, we used site-directed mutagenesis to construct thioredoxin mutants to analyze the effect on f1, M13 and T3/T7 growth. Thioredoxin mutants P34D、P34E、P34K and C35A would suppress seriously f1, M13 and T3/T7 growth at 37℃ and 42℃. Thioredoxin mutant K36R could help f1 and M13 growth at 42℃. By comparing experimental data of f1, M13 and T3/T7, we found residues 31,34,35,36 of thioredoxin could be the contact positions that thioredoxin interacts with f1 geneI protein. ii