title: Ergothioneine Biosynthesis and Functionality in the Opportunistic Fungal Pathogen, Aspergillus fumigatus.
abstract: Ergothioneine (EGT; 2-mercaptohistidine trimethylbetaine) is a trimethylated and sulphurised histidine derivative which exhibits antioxidant properties. Here we report that deletion of Aspergillus fumigatus egtA (AFUA_2G15650), which encodes a trimodular enzyme, abrogated EGT biosynthesis in this opportunistic pathogen. EGT biosynthetic deficiency in A. fumigatus significantly reduced resistance to elevated H2O2and menadione, respectively, impaired gliotoxin production and resulted in attenuated conidiation. Quantitative proteomic analysis revealed substantial proteomic remodelling in ΔegtA compared to wild-type under both basal and ROS conditions, whereby the abundance of 290 proteins was altered. Specifically, the reciprocal differential abundance of cystathionine γ-synthase and β-lyase, respectively, influenced cystathionine availability to effect EGT biosynthesis. A combined deficiency in EGT biosynthesis and the oxidative stress response regulator Yap1, which led to extreme oxidative stress susceptibility, decreased resistance to heavy metals and production of the extracellular siderophore triacetylfusarinine C and increased accumulation of the intracellular siderophore ferricrocin. EGT dissipated H2O2in vitro, and elevated intracellular GSH levels accompanied abrogation of EGT biosynthesis. EGT deficiency only decreased resistance to high H2O2levels which suggests functionality as an auxiliary antioxidant, required for growth at elevated oxidative stress conditions. Combined, these data reveal new interactions between cellular redox homeostasis, secondary metabolism and metal ion homeostasis.
authors.affiliation: Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Sheridan
authors.affiliation: Division of Molecular Biology, Biocenter, Medical University Innsbruck, Innrain 80/82, Austria.
authors.forename: Beatrix Elisabeth
authors.initials: BE
authors.lastname: Lechner
authors.affiliation: Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.
authors.forename: Grainne O'
authors.initials: GO
authors.lastname: Keeffe
authors.affiliation: Division of Biological Chemistry, Biocenter, Medical University Innsbruck, Innrain 80/82, Austria.
authors.forename: Markus A
authors.initials: MA
authors.lastname: Keller
authors.affiliation: Division of Biological Chemistry, Biocenter, Medical University Innsbruck, Innrain 80/82, Austria.
authors.forename: Ernst R
authors.initials: ER
authors.lastname: Werner
authors.affiliation: Division of Clinical Biochemistry, Biocenter, Medical University Innsbruck, Innrain 80/82, Austria.
authors.forename: Herbert
authors.initials: H
authors.lastname: Lindner
authors.affiliation: Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Jones
authors.affiliation: Division of Molecular Biology, Biocenter, Medical University Innsbruck, Innrain 80/82, Austria.
authors.forename: Hubertus
authors.initials: H
authors.lastname: Haas
authors.affiliation: Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.
authors.forename: Sean
authors.initials: S
authors.lastname: Doyle
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D001232:Aspergillus fumigatus / Q000235:genetics / Q000378:metabolism*; D019757:Carbon-Oxygen Lyases / Q000378:metabolism; D004880:Ergothioneine / Q000096:biosynthesis*; D005290:Ferric Compounds / Q000737:chemistry; D005291:Ferrichrome / Q000031:analogs & derivatives / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D005816:Genetic Complementation Test; D005912:Gliotoxin / Q000737:chemistry; D005978:Glutathione / Q000378:metabolism; D006639:Histidine / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D006877:Hydroxamic Acids / Q000737:chemistry; D008190:Lyases / Q000378:metabolism; D019216:Metals, Heavy / Q000737:chemistry; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D040901:Proteomics / Q000379:methods; D017382:Reactive Oxygen Species / Q000378:metabolism; D017262:Siderophores / Q000737:chemistry; D024483:Vitamin K 3 / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005290:Ferric Compounds; D005656:Fungal Proteins; D006877:Hydroxamic Acids; D019216:Metals, Heavy; D017382:Reactive Oxygen Species; D017262:Siderophores; D005291:Ferrichrome; C021678:ferricrocin; D006639:Histidine; C053324:N,N',N''-triacetylfusarinine C; D005912:Gliotoxin; D024483:Vitamin K 3; D006861:Hydrogen Peroxide; D004880:Ergothioneine; C022696:O-succinylhomoserine (thiol)-lyase; D008190:Lyases; D019757:Carbon-Oxygen Lyases; C019965:cystathionine beta-lyase; D005978:Glutathione