학술논문
Biosynthesis of Phloretin and Its C-Glycosides in Escherichia coli / 대장균에서 Phloretin과 그것의 C-Glycoside 생합성
Document Type
Dissertation/ Thesis
Author
Source
Subject
Language
English
Abstract
플로레틴 (phloretin)은 주로 사과와 루이보스에서 발견되는 dihydrochalcone (DHC)의 한 종류이다. 이것의 배당체인 phlorizin (phloretin 2'-O-glucoside), trilobatin (phloretin 4'-O-glucoside), 그리고 nothofagin (phloretin 3'-C-glucoside) 등은 다양한 식물에 존재한다. 플로레틴과 배당체들은 항산화, 항염, 그리고 향균 활성들을 가지고 있다. 플로레틴과 배당체들의 생합성은 식물에서 연구되었으며 합성경로는 효모와 대장균 같은 미생물에 도입되었다. 대장균에서 nothofagin과 같은 C-glycoside는 플로레틴으로부터 C-glycosyltransferase (CGT)를 이용해 합성되었다. 본 연구에서는 플로레틴과 세가지 C-glycoside들을 (Nothofagin, phloretin 3', 5'-C-di-glucoside, phloretin 3'-C-arabinoside) tyrosine으로부터 합성하기 위한 생합성경로를 대장균에 설계했다. 플로레틴이 아닌 다른 물질의 합성을 막기 위해, 전체 합성경로는 두 부분으로 나뉘었다. 첫번째 경로는 tyrosine으로부터 phloretic acid까지, 두번째 경로는 phloretic acid로부터 플로레틴과 배당체까지 합성하는 것이다. 이 방법을 사용해서 12.8 mg/L의 플로레틴, 26.1 mg/L의 nothofagin, 30.0 mg/L phloretin 3', 5'-C-di-glucoside, 그리고 18.1 mg/L phloretin 3'-C-arabinoside가 합성되었다.
Phloretin (PT) is a family of dihydrochalcones (DHCs) found mainly in apple and rooibos tea. Its glycosides, phlorizin (phloretin 2'-O-glucoside), trilobatin (phloretin 4'-O-glucoside), and nothofagin (NF, phloretin 3'-C-glucoside) are present in various plants. PT and its glycosides have health benefits including antioxidant, anti-inflammatory, and antibacterial activities. The biosynthesis of PT and its glycosides has been studied in plants and the pathway was introduced into microbial systems such as Saccharomyces cerevisiae and Escherichia coli. In E. coli, the C-glycosides of PT such as NF were synthesized by C-glycosyltransferases (CGTs) from PT. In this study, I reconstructed the biosynthesis pathway of PT and three PT C-glycosides (Nothofagin [NF], phloretin 3', 5'-C-di-glucoside [PDG], and phloretin 3'-C-arabinoside [PARA]) in E. coli to synthesize it from tyrosine. In order to prevent the synthesis of flavonoids instead of PT, the whole pathway was divided into two; the first was from tyrosine to phloretic acid (PA) and the second was from PA into PT and its glycosides. Using this approach, 12.8 mg/L PT, 26.1 mg/L NF, 30.0 mg/L PDG, and 18.1 mg/L PARA were synthesized.
Phloretin (PT) is a family of dihydrochalcones (DHCs) found mainly in apple and rooibos tea. Its glycosides, phlorizin (phloretin 2'-O-glucoside), trilobatin (phloretin 4'-O-glucoside), and nothofagin (NF, phloretin 3'-C-glucoside) are present in various plants. PT and its glycosides have health benefits including antioxidant, anti-inflammatory, and antibacterial activities. The biosynthesis of PT and its glycosides has been studied in plants and the pathway was introduced into microbial systems such as Saccharomyces cerevisiae and Escherichia coli. In E. coli, the C-glycosides of PT such as NF were synthesized by C-glycosyltransferases (CGTs) from PT. In this study, I reconstructed the biosynthesis pathway of PT and three PT C-glycosides (Nothofagin [NF], phloretin 3', 5'-C-di-glucoside [PDG], and phloretin 3'-C-arabinoside [PARA]) in E. coli to synthesize it from tyrosine. In order to prevent the synthesis of flavonoids instead of PT, the whole pathway was divided into two; the first was from tyrosine to phloretic acid (PA) and the second was from PA into PT and its glycosides. Using this approach, 12.8 mg/L PT, 26.1 mg/L NF, 30.0 mg/L PDG, and 18.1 mg/L PARA were synthesized.