Multiple Pathways for Triacylglycerol Biosynthesis in Streptomyces coelicolor
- 1 May 2008
- journal article
- Published by American Society for Microbiology in Applied and Environmental Microbiology
- Vol. 74 (9), 2573-2582
- https://doi.org/10.1128/aem.02638-07
Abstract
The terminal reaction in triacylglyceride (TAG) biosynthesis is the esterification of diacylglycerol (DAG) with a fatty acid molecule. To study this reaction in Streptomyces coelicolor , we analyzed three candidate genes (sco0958, sco1280, and sco0123) whose products significantly resemble the recently identified wax ester synthase/acyl-coenzyme A (CoA):DAG acyltransferase (DGAT) from Acinetobacter baylyi . The deletion of either sco0123 or sco1280 resulted in no detectable decrease in TAG accumulation. In contrast, the deletion of sco0958 produced a dramatic reduction in neutral lipid production, whereas the overexpression of this gene yielded a significant increase in de novo TAG biosynthesis. In vitro activity assays showed that Sco0958 mediates the esterification of DAG using long-chain acyl-CoAs (C 14 to C 18 ) as acyl donors. The K m and V max values of this enzyme for myristoyl-CoA were 45 μM and 822 nmol mg −1 min −1 , respectively. Significantly, the triple mutant strain was not completely devoid of storage lipids, indicating the existence of alternative TAG-biosynthetic routes. We present strong evidence demonstrating that the residual production of TAG in this mutant strain is mediated, at least in part, by an acyl-CoA-dependent pathway, since the triple mutant still exhibited DGAT activity. More importantly, there was substantial phospholipid:DGAT (PDAT) activity in the wild type and in the triple mutant. This is the first time that a PDAT activity has been reported for bacteria, highlighting the extreme metabolic diversity of this industrially important soil microorganism.Keywords
This publication has 39 references indexed in Scilit:
- Analysis of Storage Lipid Accumulation in Alcanivorax borkumensis : Evidence for Alternative Triacylglycerol Biosynthesis Routes in BacteriaJournal of Bacteriology, 2007
- Identification of a diacylglycerol acyltransferase gene involved in accumulation of triacylglycerol in Mycobacterium tuberculosis under stressMicrobiology, 2006
- The Wax Ester Synthase/Acyl Coenzyme A:Diacylglycerol Acyltransferase from Acinetobacter sp. Strain ADP1: Characterization of a Novel Type of AcyltransferaseJournal of Bacteriology, 2005
- Integration Site forStreptomycesPhage φBT1 and Development of Site-Specific Integrating VectorsJournal of Bacteriology, 2003
- Storage Lipid Synthesis Is Non-essential in YeastJournal of Biological Chemistry, 2002
- Over-production of Proteins inEscherichia coli: Mutant Hosts that Allow Synthesis of some Membrane Proteins and Globular Proteins at High LevelsJournal of Molecular Biology, 1996
- Biosynthesis of triacylglycerolsProgress in Lipid Research, 1996
- Influences of developmental genes on localized glycogen deposition in colonies of a mycelial prokaryote, Streptomyces coelicolor A3(2): a possible interface between metabolism and morphogenesisPhilosophical Transactions B, 1995
- Use of bacteriophage T7 RNA polymerase to direct selective high-level expression of cloned genesJournal of Molecular Biology, 1986
- Studies on transformation of Escherichia coli with plasmidsJournal of Molecular Biology, 1983