Phosphatidic Acid Phosphatase in Oleaginous Bacteria

A. ARABOLAZA, S. COMBA, S. MENENDEZ-BRAVO, H. GRAMAJO

Congreso; 11th Euro Fed Lipid Congress; 2013

Phosphatidic acid phosphatase (PAP) catalyzes the dephosphorylation of phosphatidate yielding diacylglycerol (DAG), the lipid precursor for triacylglycerol (TAG) biosynthesis. Despite the functional relevance of these proteins in lipid metabolism, no studies were conducted towards the characterization of PAP enzymes in oleaginous bacteria. The present report describes the identification of PAPs in the TAG producing bacterium Streptomyces coelicolor. We have identified two S. coelicolor genes, named lpp alpha and lpp beta, encoding for functional PAP proteins. Heterologous expression of lpp alpha and lpp beta genes in E. coli resulted in higher levels of DAG in this bacterium. In addition, the expression of these genes in yeast complemented the temperature-sensitive growth phenotype of the PAP deficient strain GHY58 (dpp1lpp1pah1). In S. coelicolor, the simultaneous mutation of both genes provoked a drastic reduction in de novo TAG biosynthesis as well as in total TAG content. Consistently, overexpression of Lpp alpha and Lpp beta in the wild type strain of S. coelicolor led to a significant increase in TAG production. Moreover, we demonstrated that the heterologous co-expression of S. coelicolor PAP and SCO0958 diacilglycerol acyltransferase (DGAT) enzymes leads to a high yield TAG biosynthesis in Escherichia coli.