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Title: Investigations of Prodiginine Biosynthesis in Streptomyces coelicolor A3(2)
Author: Stanley, Anna Elaine
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2008
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Abstract:
The prodiginines are a group of intensely red-pigmented tripyrrole compounds produced by Serratia spp., Hahella chejuensis and various actinomycetes. They are of interest due to their wide range of biological activities, including antibiotic, antitumour, immunosuppressant and anti-malarial. The proteins encoded by the red cluster, containing all of the genes required for undecylprodiginine and streptorubin B biosynthesis in Streptomyces coelicolor A3(2), were analysed in 2001 and putative functions for 18 of the 23 genes were assigned. A putative biosynthetic pathway to the prodiginines was also proposed. In this study, eight new mutants with genes in the red cluster replaced by an oriTaac( 3)W cassette, alongside two mutants from previous studies, were used to investigate the biosynthetic pathway to the prodiginines. Two biosynthetic intermediates, 4-methoxy-2,2'-bipyrrole-5-carboxaldehyde (MBC) and 2-undecylpyrrole (UP), were identified and the biosynthetic pathways to these intermediates were also studied. This was done using LC-MS analyses of acidified organic extracts of the mutants, by feeding synthetic intermediates to the mutants to observe whether prodiginine production was restored, and by a variety of cosynthesis and cross-feeding experiments. The results of these experiments were inconsistent with the previously proposed biosynthetic pathway. Using the experimental evidence obtained in this study, along with published sequence analyses of the pig cluster of Serratia spp., which directs prodigiosin biosynthesis via a common MBC intermediate, a revised complete biosynthetic pathway to the prodiginine antibiotics of S. coelicolor has been proposed. Analogues of intermediates in prodiginine biosynthesis were also synthesised and fed to the mutants to see if they could utilise modified substrates to make new prodiginine analogues. These experiments yielded natural products by mutasynthesis.
Supervisor: Not available Sponsor: Not available
Qualification Name: University of Warwick, 2008 Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.491898  DOI: Not available
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