Biosynthesis of fluoroacetate and 4-fluorothreonine in Streptomyces cattleya. Incorporation of oxygen-18 from [2-2H,2-18O]-glycerol and the role of serine metabolites in fluoroacetaldehyde biosynthesis

Abstract

A series of isotope labelling experiments was carried out to investigate the biosynthesis of fluoroacetate and 4-fluorothreonine in resting cells of Streptomyces cattleya. Previous studies have shown that fluoroacetaldehyde is a precursor to both of these metabolites and the experiments were conducted to explore in greater detail the metabolic origin of fluoroacetaldehyde in S. cattleya. Ethanolamine and cysteamine are C 2 metabolites of serine and cysteine respectively and these two metabolites emerged as candidate precursors to fluoroacetaldehyde in S. cattleya. However feeding experiments with [1,1-2 H 2 ]-ethanolamine and [1,1-2 H 2 ]-cysteamine did not indicate incorporation into the fluorometabolites, suggesting that these compounds are not relevant precursors to fluoroacetaldehyde in S. cattleya. Upon feeding [2-2 H,2-18 O]-glycerol to resting cells of S. cattleya, the deuterium atom was not incorporated into 4-fluorothreonine, however the oxygen-18 atom became incorporated into the carboxylate group of fluoroacetate and into the C(3)-O oxygen atom of 4-fluorothreonine. This observation indicates that there is an oxidation at C-2 of glycerol, but that the oxygen atom is formally retained from glycerol during the biosynthesis. In overview, the data suggest that fluoroacetaldehyde is derived from a C 3 glycolytic intermediate rather than a C 2 amino acid metabolite.

Assay for the Enantiomeric Analysis of [2H1]-Fluoroacetic Acid: Insight into the Stereochemical Course of Fluorination during Fluorometabolite Biosynthesis in Streptomyces cattleya

“…Some recent insights into the biosynthesis of fluoroacetate 1 and 4-fluorothreonine 2, in S. cattleya have been uncovered. [7][8][9][10][11][12][13] For example a biosynthetic feeding experiment with [2- 13 C]-glycerol 3a 10 resulted in isotopic incorporation into C-1 of fluoroacetate 1. Also isotopic labeling experiments with (2R) and (2S) [ 2 H 2 ]-glycerols 3b and 3c have shown 11 that the fluoromethyl groups of fluoroacetate 1 and 4-fluorothreonine 2 are labeled exclusively from the pro-R hydroxymethyl group of glycerol 3 as shown in Scheme 1.…”

Mechanism of anaerobic degradation of triethanolamine by a homoacetogenic bacterium

“…1 (1-2 H 2 )Aminoethanol (18). It was prepared by reduction of glycine methyl ester hydrochloride (17) with LiAlD 4 in THF according to Schaffrath et al [21].…”

Fluorometabolite biosynthesis and the fluorinase from Streptomyces cattleya

“…2) had revealed some general information indicating that glycine was being processed to serine via serine hydroxymethyl transferase, and that glycerol and serine were entering the glycolytic pathway. 31 However, the labelling studies did not reveal the immediate fluorination substrate. High field 19 F-NMR spectroscopy offers a very sensitive method for detecting new organo-fluorine compounds, and the prospects of identifying cell-free fluorination improved by application of this method.…”

“…Scheme 3Labelling patterns revealed the conversion of glycine to L-serine by the action of serine hydroxymethyl transferase (SHMT) prior to the incorporation of serine into fluoroacetate and C-3 and C-4 of 4-fluorothreonine, in S. cattleya 31. Soda's group in Japan demonstrated 32 in 1995 that [2-13 C]glycerol efficiently labelled C-1 of fluoroacetate 1 in S. cattleya.…”