title: Di-myo-inositol phosphate and novel UDP-sugars accumulate in the extreme hyperthermophile Pyrolobus fumarii.
abstract: The archaeon Pyrolobus fumarii, one of the most extreme members of hyperthermophiles known thus far, is able to grow at temperatures up to 113 degrees C. Over a decade after the description of this organism our knowledge about the structures and strategies underlying its remarkable thermal resistance remains incipient. The accumulation of a restricted number of charged organic solutes is a common response to heat stress in hyperthermophilic organisms and accordingly their role in thermoprotection has been often postulated. In this work, the organic solute pool of P. fumarii was characterized using 1H, 13C, and 31P NMR. Di-myo-inositol phosphate was the major solute (0.21 micromol/mg protein), reinforcing the correlation between the occurrence of this solute and hyperthermophily; in addition, UDP-sugars (total concentration 0.11 micromol/mg protein) were present. The structures of the two major UDP-sugars were identified as UDP-alpha-GlcNAc3NAc and UDP-alpha-GlcNAc3NAc-(4<--1)-beta-GlcpNAc3NAc. Interestingly, the latter compound appears to be derived from the first one by addition of a 2,3-N-acetylglucoronic acid unit, suggesting that these UDP-sugars are intermediates of an N-linked glycosylation pathway. To our knowledge the UDP-disaccharide has not been reported elsewhere. The physiological roles of these organic solutes are discussed.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, Apartado 127, 2780-156 Oeiras, Portugal.
authors.forename: Luís G
authors.initials: LG
authors.lastname: Gonçalves
authors.forename: Pedro
authors.initials: P
authors.lastname: Lamosa
authors.forename: Robert
authors.initials: R
authors.lastname: Huber
authors.forename: Helena
authors.initials: H
authors.lastname: Santos
mesh_terms: D000222:Adaptation, Physiological; D004187:Disaccharides / Q000378:metabolism; D006031:Glycosylation; D006358:Hot Temperature; D007295:Inositol Phosphates / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D041523:Pyrodictiaceae / Q000378:metabolism*; D014539:Uridine Diphosphate Sugars / Q000378:metabolism*
chemical_list: D004187:Disaccharides; D007295:Inositol Phosphates; D014539:Uridine Diphosphate Sugars; C075843:di-myo-inositol-1,1'-phosphate