Studies and application of the enzymes of fluorometabolite biosynthesis in Streptomyces cattleya

Streptomyces;Organofluorine compounds--Synthesis;Metabolites;Enzymes

Onega, Mayca ; O'Hagan, David ; O'Hagan, David

University:University of St Andrews

Department:Chemistry (School of)

关键词: Streptomyces;    Organofluorine compounds--Synthesis;    Metabolites;    Enzymes;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/991/MaycaOnegaPhDThesis.pdf?sequence=3&isAllowed=y

来源: DR-NTU

【 摘 要 】

This thesis focuses on studies investigating the structure of intermediates involved influorometabolite biosynthesis, and the potential applications of the fluorinase enzyme inpositron emission tomography (PET).Chapter 1 introduces the rare natural occurrence of fluorinated compounds. The bacteriumStreptomyces cattleya is known to biosynthesise two fluorinated secondary metabolites: thetoxin fluoroacetate (FAc) and the antibiotic 4-fluorothreonine (4-FT). The enzymes andintermediates identified on this fluorometabolite biosynthetic pathway in S. cattleya, prior tothis research, are discussed in detail.Chapter 2 presents studies towards the unambiguous structural identification of (3R,4S)-5-deoxy-5-fluoro-D-ribulose-1-phosphate (5-FRulP) as the third fluorinated intermediate on thebiosynthetic pathway to fluoroacetate and 4-fluorothreonine in S. cattleya.Chapter 3 describes the synthetic routes to key molecules, necessary as referencecompounds and substrates, to underpin the subsequent studies in this thesis. In particular,synthetic routes to 5'-deoxy-5'-fluoroadenosine (5'-FDA), 5'-deoxy-5'-fluoroinosine (5'-FDI),5-deoxy-5-fluoro-D-ribose (5-FDR) and 5-deoxy-5-fluoro-D-xylose (5-FDX) are described.Chapter 4 describes the use of the fluorinase enzyme from S. cattleya as a tool for thesynthesis of new [¹⁸F]-labelled sugars with potential application in positron emissiontomography (PET). A new route to 5-deoxy-5-[¹⁸F]fluoro-D-ribose ([¹⁸F]FDR) is developedin a two-step enzymatic synthesis. A total of three potential radiotracers ([¹⁸F]FDA,[¹⁸F]FDR and [¹⁸F]FDI) are synthesised using fluorinase-coupled enzyme reactions.In addition, in vitro studies are reported with these [¹⁸F]-labelled sugars to investigate theiruptake and potential as PET radiotracers in cancer cells. A preliminary rat imaging study with[¹⁸F]FDA is reported.Chapter 5 details the experimental procedures for the compounds synthesised in thisresearch and the biological procedures for chemo-enzymatic syntheses and proteinpurification.