title: Occurrence of 1-glyceryl-1-myo-inosityl phosphate in hyperthermophiles.
abstract: The accumulation of compatible solutes was studied in the hyperthermophilic bacterium Aquifex pyrophilus as a function of the temperature and the NaCl concentration of the growth medium. Nuclear magnetic resonance analysis of cell extracts revealed the presence of alpha- and beta-glutamate, di-mannosyl-di-myo-inositol phosphate, di-myo-inositol phosphate, and an additional compound here identified as 1-glyceryl-1-myo-inosityl phosphate. All solutes accumulated by A. pyrophilus are negatively charged at physiological pH. The intracellular levels of di-myo-inositol phosphate increased in response to supraoptimal growth temperature, while alpha- and beta-glutamate accumulated in response to osmotic stress, especially at growth temperatures below the optimum. The newly discovered compound, 1-glyceryl-1-myo-inosityl phosphate, appears to play a double role in osmo- and thermoprotection, since its intracellular pool increased primarily in response to a combination of osmotic and heat stresses. This work also uncovered the nature of the unknown compound, previously detected in Archaeoglobus fulgidus (L. O. Martins et al., Appl. Environ. Microbiol. 63:896-902, 1997). The curious structural relationship between diglycerol phosphate (found only in Archaeoglobus species), di-myo-inositol phosphate (a canonical solute of hyperthermophiles), and the newly identified solute is highlighted. This is the first report on the occurrence of 1-glyceryl-1-myo-inosityl phosphate in living systems.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2780-156 Oeiras, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Lamosa
authors.forename: Luís G
authors.initials: LG
authors.lastname: Gonçalves
authors.forename: Marta V
authors.initials: MV
authors.lastname: Rodrigues
authors.forename: Lígia O
authors.initials: LO
authors.lastname: Martins
authors.forename: Neil D H
authors.initials: ND
authors.lastname: Raven
authors.forename: Helena
authors.initials: H
authors.lastname: Santos
mesh_terms: D019611:Archaeoglobus fulgidus / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D017753:Ecosystem; D006358:Hot Temperature; D007295:Inositol Phosphates / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D012965:Sodium Chloride
chemical_list: D007295:Inositol Phosphates; D012965:Sodium Chloride