Identification and metabolism studies of fluorometabolites from different Streptomyces

Organofluorine compounds;Microbial metabolites;Streptomyces

Bartholomé, Axel ; O'Hagan, David ; O'Hagan, David

University:University of St Andrews

Department:Chemistry (School of)

关键词: Organofluorine compounds;    Microbial metabolites;    Streptomyces;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/15592/AxelBartholomePhDThesis.pdf?sequence=2&isAllowed=y

来源: DR-NTU

【 摘 要 】

To date, only five fluorinated natural products have been identified. These were isolated fromboth plants and bacteria. The bacterium Streptomyces cattleya has the ability to biosynthesisefluoroacetate and 4-fluoro-L-threonine. The first enzyme discovered to be capable ofcatalysing a C-F bond from fluoride ion, the fluorinase, was identified from S. cattleya in 2002and is involved in the first step in the biosynthesis of fluorometabolites. The completemetabolic pathway of fluoroacetate and 4-fluoro-L-threonine in S. cattleya was elucidatedutilising a variety of different techniques.Recently, genome studies revealed the presence of four new fluorinase enzymes fromdifferent bacterial species. Cultures of one of these species, named Streptomyces sp. MA37,showed the production of new unidentified fluorometabolites. Over-expression of the FdrCgene from Streptomyces sp. MA37 was performed, and enzymatic assays of the FdrC enzymeallowed the conversion of 5-fluoro-5-deoxy-ribose to (2R,3S,4S)-5-fluoro-2,3,4-trihydroxypentanoic acid. Identification of (2R,3S,4S)-5-fluoro-2,3,4-trihydroxypentanoic acidas a new fluorometabolite was then confirmed by synthetic synthesis.Nucleocidin, an antibiotic containing fluorine, was isolated in 1957 from the soil bacterium,Streptomyces calvus. Since its isolation, attempts at re-establishing nucleocidin producingcultures have proven unsuccessful. The biosynthesis of nucleocidin involves a C-F bond-forming enzyme unique to Streptomyces calvus. Production of a commercial strain from Pfizerwas established and isotopic labelling studies with different labelled glycerols were completed.Pulse feeding experiments with (2R)-[1- ²H₂]-glycerol, (2S)-[1-²H₂]-glycerol, glycerol-1,1,2,3,3-d₅ and [2-¹³ C]-glycerol proved to be successful. Concomitantly, synthesis of highly pure putative substrates for the fluorinating enzyme was carried out. Unfortunately, cell-free extract experiments were achieved, but results from these were not conclusive.