Components and Key Regulatory Steps of Lipid Biosynthesis in Actinomycetes

Abstract

The biochemical steps in fatty acid synthesis are highly conserved in bacteria andin most organisms. However, the data provided by the massive genomic sequencingrevealed a surprising amount of diversity in the genes, enzymes, and geneticorganization of the components responsible for bacterial lipid synthesis, withthese differences being even more striking in the order Actinomycetales. Fattyacid biosynthesis is energetically very expensive for the cell; therefore, adjustingthe rate of fatty acid synthesis, in order to maintain membrane lipid homeostasis,is a key factor for bacterial survival. Bacteria have evolved sophisticated anddiverse mechanisms to finely control the expression of the genes responsible forthe synthesis of fatty acids and, in some cases, also by regulating the activity ofthe pacemaker enzymes. In this chapter we summarize the main components offatty acid biosynthesis and their regulation in different genera of actinomycetes,highlighting the main differences found between them and also with otherbacteria. The main focus has been put into the acyl-CoA carboxylases, the fattyacid synthases, and on the regulatory elements that control these pathways.