Osmotically Induced Synthesis of the Compatible Solute Hydroxyectoine Is Mediated by an Evolutionarily Conserved Ectoine Hydroxylase

摘要: By using natural abundance (13)C NMR spectroscopy, we investigated the types of compatible solutes synthesized in a variety Bacilli under high salinity growth conditions. Glutamate, proline, and ectoine were dominant by various Bacillus species. The majority inspected produced tetrahydropyrimidine response to stress, subset these also hydroxylation derivative ectoine, 5-hydroxyectoine. In Salibacillus salexigens, representative ectoine- 5-hydroxyectoine-producing species, production was linearly correlated with medium dependent on an ectABC biosynthetic operon. formation 5-hydroxyectoine primarily stationary phase phenomenon. enzyme responsible for (EctD) purified from S. salexigens apparent homogeneity. EctD protein shown vitro directly hydroxylate reaction iron(II), molecular oxygen, 2-oxoglutarate. We identified structural gene (ectD) hydroxylase salexigens. Northern blot analysis showed that transcript levels ectD genes increased as function salinity. Many EctD-related proteins can be found data base searches Bacteria. Each bacterial species contains cluster, suggesting biosynthesis strictly depends prior synthesis ectoine. Our biochemical characterization suggest hydroxylases are members new subfamily within non-heme-containing, iron(II)- 2-oxoglutarate-dependent dioxygenase superfamily (EC 1.14.11).