Identification of a gene required for the formation of lyso‐ornithine lipid, an intermediate in the biosynthesis of ornithine‐containing lipids

摘要: Under phosphate-limiting conditions, some bacteria replace their membrane phospholipids by lipids not containing any phosphorus. One of these phosphorus-free is an ornithine-containing lipid (OL) that widespread among eubacteria. In earlier work, we had identified a gene (olsA) required for OL biosynthesis probably encodes O-acyltransferase using acyl-acyl carrier protein (acyl-AcpP) as acyl donor and converts lyso-ornithine into OL. We now report on second (olsB) needed the incorporation radiolabelled ornithine Overexpression OlsB in olsA-deficient mutant Sinorhizobium (Rhizobium) meliloti leads to transient accumulation lipid, biosynthetic intermediate biosynthesis. Escherichia coli sufficient cause vivo formation this organism 3-hydroxyacyl-AcpP-dependent acyltransferase activity forming from ornithine. These results demonstrate first step biosynthesis, which N-acylated with 3-hydroxy-fatty residue order obtain lipid. wild-type S. increased upon growth under conditions. Expression broad host range vector constitutive relatively high amounts (12-14% total lipids) independently whether strains are grown presence low or concentrations phosphate, suggesting usually limiting amount formed organism. Open reading frames homologous OlsA were many eubacteria although olsB olsA 14 kb apart, numerous other they form operon.