Abstract
Obtaining information about a biosynthetic pathway is a complex and laborious procedure. In this sense, this work presents a new approach for the initial analysis of the biosynthesis of fluorescent natural products using as example the violacein biosynthesis. For this, a culture of Chromobacterium violaceum was grown in a bioreactor from which aliquots were collected every 2 h for subsequent analysis by multi-wavelength fluorescence spectroscopy. The excitation-emission matrices demonstrated the dynamic behavior of the fluorophores signal that are consumed and produced by the bacterium. These signals were resolved by PARAFAC (parallel factor analysis) method totalizing six pure components. Tryptophan and violacein were identified by comparison to spectra available in the literature. The identification of other fluorophores was critical step due to the lack of a database of fluorescent natural products to compare spectra. Finally, this methodology has great potential to achieve a deeper insight into the biosynthesis of natural products.
Highlights
Natural products have had historical success as biologically active structures
From 1987 to 1990, Hoshino et al.[7,8,9] demonstrated that (i) the carbon skeleton of the pyrrolidone moiety was built up by the condensation of the side chains of two L-tryptophan molecules accompanied by the 1,2-shift of the indole ring on one molecule of tryptophan;[7] (ii) all carbon, nitrogen and hydrogen atoms in the pyrrolidone moiety were provided exclusively by L-tryptophan and that the oxygen atoms come from molecular oxygen;[8] and (iii) the intermediacy of 5-hydroxy-L-tryptophan in the violacein biosynthesis since the hydroxylation of tryptophan was the first step of violacein biosynthesis.[9]
Fluorescence data The fluorescence data set consisted of 18 excitation‐emission matrices (EEMs) of ethanolic extracts of C. violaceum collected at different stages of violacein biosynthesis
Summary
Natural products have had historical success as biologically active structures. Among these, the violet pigment, named violacein, produced mainly by bacteria of the genus Chromobacterium has attracted increased interest owing to its important biological activities and pharmacological and industrial potentials.[1,2]Violacein (Figure 1) is a secondary metabolite with a molar mass of 343.3 amu and is constituted of 5-hydroxyindole, 2-pyrrolidone and 2-oxindole moieties that show strong absorption in the visible region due to resonance.[3]Studies about violacein biosynthesis began in 1934 with Tobie,[4] who observed that oxygenation of a Chromobacterium violaceum culture greatly reduced the time required for maximum pigment production. It consists in employing multiwavelength fluorescence spectroscopy and PARAFAC method to detect and identify (through spectral resolution) fluorophores that are consumed and produced by a bacterium and, to establish a relationship with the natural product biosynthesis.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
