UDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase

ABSTRACT Can accumulation of a normally transient metabolite affect fungal biology? UDP-4-keto-6-deoxyglucose (UDP-KDG) represents an intermediate stage in conversion of UDP-glucose to UDP-rhamnose. Normally, UDP-KDG is not detected in living cells, because it is quickly converted to UDP-rhamnose by...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Liang Ma, Omar Salas, Kyle Bowler, Maor Bar-Peled, Amir Sharon
Formato: article
Lenguaje:EN
Publicado: American Society for Microbiology 2017
Materias:
Acceso en línea:https://doaj.org/article/64f60381e6044febbf061053744506f0
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
id oai:doaj.org-article:64f60381e6044febbf061053744506f0
record_format dspace
spelling oai:doaj.org-article:64f60381e6044febbf061053744506f02021-11-15T15:51:55ZUDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase10.1128/mBio.01559-172150-7511https://doaj.org/article/64f60381e6044febbf061053744506f02017-12-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01559-17https://doaj.org/toc/2150-7511ABSTRACT Can accumulation of a normally transient metabolite affect fungal biology? UDP-4-keto-6-deoxyglucose (UDP-KDG) represents an intermediate stage in conversion of UDP-glucose to UDP-rhamnose. Normally, UDP-KDG is not detected in living cells, because it is quickly converted to UDP-rhamnose by the enzyme UDP-4-keto-6-deoxyglucose-3,5-epimerase/-4-reductase (ER). We previously found that deletion of the er gene in Botrytis cinerea resulted in accumulation of UDP-KDG to levels that were toxic to the fungus due to destabilization of the cell wall. Here we show that these negative effects are at least partly due to inhibition by UDP-KDG of the enzyme UDP-galactopyranose mutase (UGM), which reversibly converts UDP-galactopyranose (UDP-Galp) to UDP-galactofuranose (UDP-Galf). An enzymatic activity assay showed that UDP-KDG inhibits the B. cinerea UGM enzyme with a Ki of 221.9 µM. Deletion of the ugm gene resulted in strains with weakened cell walls and phenotypes that were similar to those of the er deletion strain, which accumulates UDP-KDG. Galf residue levels were completely abolished in the Δugm strain and reduced in the Δer strain, while overexpression of the ugm gene in the background of a Δer strain restored Galf levels and alleviated the phenotypes. Collectively, our results show that the antifungal activity of UDP-KDG is due to inhibition of UGM and possibly other nucleotide sugar-modifying enzymes and that the rhamnose metabolic pathway serves as a shunt that prevents accumulation of UDP-KDG to toxic levels. These findings, together with the fact that there is no Galf in mammals, support the possibility of developing UDP-KDG or its derivatives as antifungal drugs. IMPORTANCE Nucleotide sugars are donors for the sugars in fungal wall polymers. We showed that production of the minor sugar rhamnose is used primarily to neutralize the toxic intermediate compound UDP-KDG. This surprising finding highlights a completely new role for minor sugars and other secondary metabolites with undetermined function. Furthermore, the toxic potential of predicted transition metabolites that never accumulate in cells under natural conditions are highlighted. We demonstrate that UDP-KDG inhibits the UDP-galactopyranose mutase enzyme, thereby affecting production of Galf, which is one of the components of cell wall glycans. Given the structural similarity, UDP-KDG likely inhibits additional nucleotide sugar-utilizing enzymes, a hypothesis that is also supported by our findings. Our results suggest that UDP-KDG could serve as a template to develop antifungal drugs.Liang MaOmar SalasKyle BowlerMaor Bar-PeledAmir SharonAmerican Society for MicrobiologyarticleBotrytis cinereaUDP-4-keto-6-deoxyglucoseUDP-galactopyranose mutasefungal cell wallfungal nucleotide sugar metabolismgalactofuranoseMicrobiologyQR1-502ENmBio, Vol 8, Iss 6 (2017)
institution DOAJ
collection DOAJ
language EN
topic Botrytis cinerea
UDP-4-keto-6-deoxyglucose
UDP-galactopyranose mutase
fungal cell wall
fungal nucleotide sugar metabolism
galactofuranose
Microbiology
QR1-502
spellingShingle Botrytis cinerea
UDP-4-keto-6-deoxyglucose
UDP-galactopyranose mutase
fungal cell wall
fungal nucleotide sugar metabolism
galactofuranose
Microbiology
QR1-502
Liang Ma
Omar Salas
Kyle Bowler
Maor Bar-Peled
Amir Sharon
UDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase
description ABSTRACT Can accumulation of a normally transient metabolite affect fungal biology? UDP-4-keto-6-deoxyglucose (UDP-KDG) represents an intermediate stage in conversion of UDP-glucose to UDP-rhamnose. Normally, UDP-KDG is not detected in living cells, because it is quickly converted to UDP-rhamnose by the enzyme UDP-4-keto-6-deoxyglucose-3,5-epimerase/-4-reductase (ER). We previously found that deletion of the er gene in Botrytis cinerea resulted in accumulation of UDP-KDG to levels that were toxic to the fungus due to destabilization of the cell wall. Here we show that these negative effects are at least partly due to inhibition by UDP-KDG of the enzyme UDP-galactopyranose mutase (UGM), which reversibly converts UDP-galactopyranose (UDP-Galp) to UDP-galactofuranose (UDP-Galf). An enzymatic activity assay showed that UDP-KDG inhibits the B. cinerea UGM enzyme with a Ki of 221.9 µM. Deletion of the ugm gene resulted in strains with weakened cell walls and phenotypes that were similar to those of the er deletion strain, which accumulates UDP-KDG. Galf residue levels were completely abolished in the Δugm strain and reduced in the Δer strain, while overexpression of the ugm gene in the background of a Δer strain restored Galf levels and alleviated the phenotypes. Collectively, our results show that the antifungal activity of UDP-KDG is due to inhibition of UGM and possibly other nucleotide sugar-modifying enzymes and that the rhamnose metabolic pathway serves as a shunt that prevents accumulation of UDP-KDG to toxic levels. These findings, together with the fact that there is no Galf in mammals, support the possibility of developing UDP-KDG or its derivatives as antifungal drugs. IMPORTANCE Nucleotide sugars are donors for the sugars in fungal wall polymers. We showed that production of the minor sugar rhamnose is used primarily to neutralize the toxic intermediate compound UDP-KDG. This surprising finding highlights a completely new role for minor sugars and other secondary metabolites with undetermined function. Furthermore, the toxic potential of predicted transition metabolites that never accumulate in cells under natural conditions are highlighted. We demonstrate that UDP-KDG inhibits the UDP-galactopyranose mutase enzyme, thereby affecting production of Galf, which is one of the components of cell wall glycans. Given the structural similarity, UDP-KDG likely inhibits additional nucleotide sugar-utilizing enzymes, a hypothesis that is also supported by our findings. Our results suggest that UDP-KDG could serve as a template to develop antifungal drugs.
format article
author Liang Ma
Omar Salas
Kyle Bowler
Maor Bar-Peled
Amir Sharon
author_facet Liang Ma
Omar Salas
Kyle Bowler
Maor Bar-Peled
Amir Sharon
author_sort Liang Ma
title UDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase
title_short UDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase
title_full UDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase
title_fullStr UDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase
title_full_unstemmed UDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase
title_sort udp-4-keto-6-deoxyglucose, a transient antifungal metabolite, weakens the fungal cell wall partly by inhibition of udp-galactopyranose mutase
publisher American Society for Microbiology
publishDate 2017
url https://doaj.org/article/64f60381e6044febbf061053744506f0
work_keys_str_mv AT liangma udp4keto6deoxyglucoseatransientantifungalmetaboliteweakensthefungalcellwallpartlybyinhibitionofudpgalactopyranosemutase
AT omarsalas udp4keto6deoxyglucoseatransientantifungalmetaboliteweakensthefungalcellwallpartlybyinhibitionofudpgalactopyranosemutase
AT kylebowler udp4keto6deoxyglucoseatransientantifungalmetaboliteweakensthefungalcellwallpartlybyinhibitionofudpgalactopyranosemutase
AT maorbarpeled udp4keto6deoxyglucoseatransientantifungalmetaboliteweakensthefungalcellwallpartlybyinhibitionofudpgalactopyranosemutase
AT amirsharon udp4keto6deoxyglucoseatransientantifungalmetaboliteweakensthefungalcellwallpartlybyinhibitionofudpgalactopyranosemutase
_version_ 1718427339651547136