title: CGDEase, a Pseudomonas fluorescens protein of the PLC/APase superfamily with CDP-ethanolamine and (dihexanoyl)glycerophosphoethanolamine hydrolase activity induced by osmoprotectants under phosphate-deficient conditions.
abstract: A novel enzyme, induced by choline, ethanolamine, glycine betaine or dimethylglycine, was released at low temperature and phosphate from Pseudomonas fluorescens (CECT 7229) suspensions at low cell densities. It is a CDP-ethanolamine pyrophosphatase/(dihexanoyl)glycerophosphoethanolamine phosphodiesterase (CGDEase) less active on choline derivatives, and inactive on long-chain phospholipids, CDP-glycerol and other NDP-X compounds. The reaction pattern was typical of phospholipase C (PLC), as either phosphoethanolamine or phosphocholine was produced. Peptide-mass analyses, gene cloning and expression provided a molecular identity for CGDEase. Bioinformatic studies assigned it to the PLC branch of the phospholipase C/acid phosphatase (PLC/APase) superfamily, revealed an irregular phylogenetic distribution of close CGDEase relatives, and suggested their genes are not in operons or conserved contexts. A theoretical CGDEase structure was supported by mutagenesis of two predicted active-site residues, which yielded essentially inactive mutants. Biological relevance is supported by comparisons with CGDEase relatives, induction by osmoprotectants (not by osmotic stress itself) and repression by micromolar phosphate. The low bacterial density requirement was related to phosphate liberation from lysed bacteria in denser populations, rather than to a classical quorum-sensing effect. The results fit better a CGDEase role in phosphate scavenging than in osmoprotection.
authors.affiliation: Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, Badajoz E-06006, Spain.
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Costas
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Pinto
authors.forename: Paloma Martín
authors.initials: PM
authors.lastname: Cordero
authors.forename: Alicia
authors.initials: A
authors.lastname: Cabezas
authors.forename: Isabel
authors.initials: I
authors.lastname: Alves-Pereira
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Cameselle
authors.forename: João Meireles
authors.initials: JM
authors.lastname: Ribeiro
mesh_terms: D020134:Catalytic Domain; D003565:Cytidine Diphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D004983:Ethanolamines / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D005810:Multigene Family; D010710:Phosphates / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011551:Pseudomonas fluorescens / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D011755:Pyrophosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D000099189:Lysophospholipase D
chemical_list: D003565:Cytidine Diphosphate; D004983:Ethanolamines; D010710:Phosphates; D010727:Phosphoric Diester Hydrolases; D011755:Pyrophosphatases; D000099189:Lysophospholipase D; C006933:CDP ethanolamine