Publications

• A bifunctional salvage pathway for two distinct S-adenosylmethionine by-products that is widespread in bacteria, including pathogenic Escherichia coli.

  North J.A., Wildenthal J.A., Erb T.J., Evans B.S., Byerly K.M., Gerlt J.A., Tabita F.R.

  S-adenosyl-l-methionine (SAM) is a necessary cosubstrate for numerous essential enzymatic reactions including protein and nucleotide methylations, secondary metabolite synthesis and radical-mediated processes. Radical SAM enzymes produce 5'-deoxyadenosine, and SAM-dependent enzymes for polyamine, ... >> More

  S-adenosyl-l-methionine (SAM) is a necessary cosubstrate for numerous essential enzymatic reactions including protein and nucleotide methylations, secondary metabolite synthesis and radical-mediated processes. Radical SAM enzymes produce 5'-deoxyadenosine, and SAM-dependent enzymes for polyamine, neurotransmitter and quorum sensing compound synthesis produce 5'-methylthioadenosine as by-products. Both are inhibitory and must be addressed by all cells. This work establishes a bifunctional oxygen-independent salvage pathway for 5'-deoxyadenosine and 5'-methylthioadenosine in both Rhodospirillum rubrum and Extraintestinal Pathogenic Escherichia coli. Homologous genes for this pathway are widespread in bacteria, notably pathogenic strains within several families. A phosphorylase (Rhodospirillum rubrum) or separate nucleoside and kinase (Escherichia coli) followed by an isomerase and aldolase sequentially function to salvage these two wasteful and inhibitory compounds into adenine, dihydroxyacetone phosphate and acetaldehyde or (2-methylthio)acetaldehyde during both aerobic and anaerobic growth. Both SAM by-products are metabolized with equal affinity during aerobic and anaerobic growth conditions, suggesting that the dual-purpose salvage pathway plays a central role in numerous environments, notably the human body during infection. Our newly discovered bifunctional oxygen-independent pathway, widespread in bacteria, salvages at least two by-products of SAM-dependent enzymes for carbon and sulfur salvage, contributing to cell growth. << Less

  Mol. Microbiol. 113:923-937(2020) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Salvage of the 5-deoxyribose byproduct of radical SAM enzymes.

  Beaudoin G.A.W., Li Q., Folz J., Fiehn O., Goodsell J.L., Angerhofer A., Bruner S.D., Hanson A.D.

  5-Deoxyribose is formed from 5'-deoxyadenosine, a toxic byproduct of radical S-adenosylmethionine (SAM) enzymes. The degradative fate of 5-deoxyribose is unknown. Here, we define a salvage pathway for 5-deoxyribose in bacteria, consisting of phosphorylation, isomerization, and aldol cleavage steps ... >> More

  5-Deoxyribose is formed from 5'-deoxyadenosine, a toxic byproduct of radical S-adenosylmethionine (SAM) enzymes. The degradative fate of 5-deoxyribose is unknown. Here, we define a salvage pathway for 5-deoxyribose in bacteria, consisting of phosphorylation, isomerization, and aldol cleavage steps. Analysis of bacterial genomes uncovers widespread, unassigned three-gene clusters specifying a putative kinase, isomerase, and sugar phosphate aldolase. We show that the enzymes encoded by the Bacillus thuringiensis cluster, acting together in vitro, convert 5-deoxyribose successively to 5-deoxyribose 1-phosphate, 5-deoxyribulose 1-phosphate, and dihydroxyacetone phosphate plus acetaldehyde. Deleting the isomerase decreases the 5-deoxyribulose 1-phosphate pool size, and deleting either the isomerase or the aldolase increases susceptibility to 5-deoxyribose. The substrate preference of the aldolase is unique among family members, and the X-ray structure reveals an unusual manganese-dependent enzyme. This work defines a salvage pathway for 5-deoxyribose, a near-universal metabolite. << Less

  Nat. Commun. 9:3105-3105(2018) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• <i>Escherichia coli</i> possessing the dihydroxyacetone phosphate shunt utilize 5'-deoxynucleosides for growth.

  Huening K.A., Groves J.T., Wildenthal J.A., Tabita F.R., North J.A.

  All organisms utilize <i>S</i>-adenosyl-l-methionine (SAM) as a key co-substrate for the methylation of biological molecules, the synthesis of polyamines, and radical SAM reactions. When these processes occur, 5'-deoxy-nucleosides are formed as byproducts such as <i>S</i>-adenosyl-l-homocysteine, ... >> More

  All organisms utilize <i>S</i>-adenosyl-l-methionine (SAM) as a key co-substrate for the methylation of biological molecules, the synthesis of polyamines, and radical SAM reactions. When these processes occur, 5'-deoxy-nucleosides are formed as byproducts such as <i>S</i>-adenosyl-l-homocysteine, 5'-methylthioadenosine (MTA), and 5'-deoxyadenosine (5dAdo). A prevalent pathway found in bacteria for the metabolism of MTA and 5dAdo is the dihydroxyacetone phosphate (DHAP) shunt, which converts these compounds into dihydroxyacetone phosphate and 2-methylthioacetaldehyde or acetaldehyde, respectively. Previous work in other organisms has shown that the DHAP shunt can enable methionine synthesis from MTA or serve as an MTA and 5dAdo detoxification pathway. Rather, the DHAP shunt in <i>Escherichia coli</i> ATCC 25922, when introduced into <i>E. coli</i> K-12, enables the use of 5dAdo and MTA as a carbon source for growth. When MTA is the substrate, the sulfur component is not significantly recycled back to methionine but rather accumulates as 2-methylthioethanol, which is slowly oxidized non-enzymatically under aerobic conditions. The DHAP shunt in ATCC 25922 is active under oxic and anoxic conditions. Growth using 5-deoxy-d-ribose was observed during aerobic respiration and anaerobic respiration with Trimethylamine N-oxide (TMAO), but not during fermentation or respiration with nitrate. This suggests the DHAP shunt may only be relevant for extraintestinal pathogenic <i>E. coli</i> lineages with the DHAP shunt that inhabit oxic or TMAO-rich extraintestinal environments. This reveals a heretofore overlooked role of the DHAP shunt in carbon and energy metabolism from ubiquitous SAM utilization byproducts and suggests a similar role may occur in other pathogenic and non-pathogenic bacteria with the DHAP shunt.<h4>Importance</h4>The acquisition and utilization of organic compounds that serve as growth substrates are essential for <i>Escherichia coli</i> to grow and multiply. Ubiquitous enzymatic reactions involving S-adenosyl-l-methionine as a co-substrate by all organisms result in the formation of the 5'-deoxy-nucleoside byproducts, 5'-methylthioadenosine and 5'-deoxyadenosine. All <i>E. coli</i> possess a conserved nucleosidase that cleaves these 5'-deoxy-nucleosides into 5-deoxy-pentose sugars for adenine salvage. The DHAP shunt pathway is found in some extraintestinal pathogenic <i>E. coli</i>, but its function in <i>E. coli</i> possessing it has remained unknown. This study reveals that the DHAP shunt enables the utilization of 5'-deoxy-nucleosides and 5-deoxy-pentose sugars as growth substrates in <i>E. coli</i> strains with the pathway during aerobic respiration and anaerobic respiration with TMAO, but not fermentative growth. This provides an insight into the diversity of sugar compounds accessible by <i>E. coli</i> with the DHAP shunt and suggests that the DHAP shunt is primarily relevant in oxic or TMAO-rich extraintestinal environments. << Less

  Microbiol Spectr 12:e0308623-e0308623(2024) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.