Exploration and engineering of biosynthetic pathways in the marine actinomycete Salinispora tropica

In recent years, members of the marine actinomycete genus Salinispora have proven to be a precious source of structurally diverse secondary metabolites, including the potent anticancer agent salinosporamide A and the enediyne-derived sporolides. The tremendous potential of these marine-dwelling microbes for natural products biosynthesis, however, was not fully realized until sequencing of the Salinispora tropica genome revealed the presence of numerous orphan biosynthetic loci besides a plethora of rare metabolic pathways. This contribution summarizes the biochemical exploration of this prolific organism, highlighting studies in which genome-based information was exploited for the discovery of new enzymatic processes and the engineering of unnatural natural products. Inactivation of key genes within the salinosporamide pathway has expanded its inherent metabolic plasticity and enabled access to various salinosporamide derivatives by mutasynthesis. New insights into the biosynthesis of the sporolides allowed us to increase production titers of these structurally complex molecules, thereby providing the means to search for the DNA cleaving presporolide enediyne.