An Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis

ABSTRACT Metabolism consists of biochemical reactions that are combined to generate a robust metabolic network that can respond to perturbations and also adapt to changing environmental conditions. Escherichia coli and Salmonella enterica are closely related enterobacteria that share metabolic compo...

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Autores principales:	Jannell V. Bazurto, Kristen R. Farley, Diana M. Downs
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2016
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/b7e97a336cfd47d98bb19b5793785c55
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spelling	oai:doaj.org-article:b7e97a336cfd47d98bb19b5793785c552021-11-15T15:49:39ZAn Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis10.1128/mBio.01840-152150-7511https://doaj.org/article/b7e97a336cfd47d98bb19b5793785c552016-03-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01840-15https://doaj.org/toc/2150-7511ABSTRACT Metabolism consists of biochemical reactions that are combined to generate a robust metabolic network that can respond to perturbations and also adapt to changing environmental conditions. Escherichia coli and Salmonella enterica are closely related enterobacteria that share metabolic components, pathway structures, and regulatory strategies. The synthesis of thiamine in S. enterica has been used to define a node of the metabolic network by analyzing alternative inputs to thiamine synthesis from diverse metabolic pathways. To assess the conservation of metabolic networks in organisms with highly conserved components, metabolic contributions to thiamine synthesis in E. coli were investigated. Unexpectedly, we found that, unlike S. enterica, E. coli does not use the phosphoribosylpyrophosphate (PRPP) amidotransferase (PurF) as the primary enzyme for synthesis of phosphoribosylamine (PRA). In fact, our data showed that up to 50% of the PRA used by E. coli to make thiamine requires the activities of threonine dehydratase (IlvA) and anthranilate synthase component II (TrpD). Significantly, the IlvA- and TrpD-dependent pathway to PRA functions in S. enterica only in the absence of a functional reactive intermediate deaminase (RidA) enzyme, bringing into focus how these closely related bacteria have distinct metabolic networks. IMPORTANCE In most bacteria, including Salmonella strains and Escherichia coli, synthesis of the pyrimidine moiety of the essential coenzyme, thiamine pyrophosphate (TPP), shares enzymes with the purine biosynthetic pathway. Phosphoribosylpyrophosphate amidotransferase, encoded by the purF gene, generates phosphoribosylamine (PRA) and is considered the first enzyme in the biosynthesis of purines and the pyrimidine moiety of TPP. We show here that, unlike Salmonella, E. coli synthesizes significant thiamine from PRA derived from threonine using enzymes from the isoleucine and tryptophan biosynthetic pathways. These data show that two closely related organisms can have distinct metabolic network structures despite having similar enzyme components, thus emphasizing caveats associated with predicting metabolic potential from genome content.Jannell V. BazurtoKristen R. FarleyDiana M. DownsAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 7, Iss 1 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Jannell V. Bazurto Kristen R. Farley Diana M. Downs An Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis
description	ABSTRACT Metabolism consists of biochemical reactions that are combined to generate a robust metabolic network that can respond to perturbations and also adapt to changing environmental conditions. Escherichia coli and Salmonella enterica are closely related enterobacteria that share metabolic components, pathway structures, and regulatory strategies. The synthesis of thiamine in S. enterica has been used to define a node of the metabolic network by analyzing alternative inputs to thiamine synthesis from diverse metabolic pathways. To assess the conservation of metabolic networks in organisms with highly conserved components, metabolic contributions to thiamine synthesis in E. coli were investigated. Unexpectedly, we found that, unlike S. enterica, E. coli does not use the phosphoribosylpyrophosphate (PRPP) amidotransferase (PurF) as the primary enzyme for synthesis of phosphoribosylamine (PRA). In fact, our data showed that up to 50% of the PRA used by E. coli to make thiamine requires the activities of threonine dehydratase (IlvA) and anthranilate synthase component II (TrpD). Significantly, the IlvA- and TrpD-dependent pathway to PRA functions in S. enterica only in the absence of a functional reactive intermediate deaminase (RidA) enzyme, bringing into focus how these closely related bacteria have distinct metabolic networks. IMPORTANCE In most bacteria, including Salmonella strains and Escherichia coli, synthesis of the pyrimidine moiety of the essential coenzyme, thiamine pyrophosphate (TPP), shares enzymes with the purine biosynthetic pathway. Phosphoribosylpyrophosphate amidotransferase, encoded by the purF gene, generates phosphoribosylamine (PRA) and is considered the first enzyme in the biosynthesis of purines and the pyrimidine moiety of TPP. We show here that, unlike Salmonella, E. coli synthesizes significant thiamine from PRA derived from threonine using enzymes from the isoleucine and tryptophan biosynthetic pathways. These data show that two closely related organisms can have distinct metabolic network structures despite having similar enzyme components, thus emphasizing caveats associated with predicting metabolic potential from genome content.
format	article
author	Jannell V. Bazurto Kristen R. Farley Diana M. Downs
author_facet	Jannell V. Bazurto Kristen R. Farley Diana M. Downs
author_sort	Jannell V. Bazurto
title	An Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis
title_short	An Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis
title_full	An Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis
title_fullStr	An Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis
title_full_unstemmed	An Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis
title_sort	unexpected route to an essential cofactor: <named-content content-type="genus-species">escherichia coli</named-content> relies on threonine for thiamine biosynthesis
publisher	American Society for Microbiology
publishDate	2016
url	https://doaj.org/article/b7e97a336cfd47d98bb19b5793785c55
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An Unexpected Route to an Essential Cofactor: <named-content content-type="genus-species">Escherichia coli</named-content> Relies on Threonine for Thiamine Biosynthesis

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