Protein‐protein Interactions and Acyl Carrier Protein Recognition in the Biosynthesis of Omega‐3 Fatty Acids by a Polyketide Synthase

Acyl carrier protein (ACP) is a highly conserved protein domain that participates in the biosynthesis of fatty acids and polyketides. Most enzyme complexes contain either one or many of these domains arranged in a modular fashion. However, the polyketide synthase (PKS) complex responsible for the production of omega‐3 fatty acids in deep‐sea bacteria contains a total of five ACP domains in tandem, with no obvious reason as to why this particular arrangement has been widely selected throughout nature. One possible explanation is that different ACP domains have different binding specificities towards the enzyme domains which “service” them. In order to investigate whether ACP domains have specificity toward other enzyme domains, we have expressed ACP domains individually in E. coli and purified them using a combination of nickel chromatography and anion exchange chromatography. Each individual ACP will be assayed for binding to the different purified enzyme domains, such as the thioesterase, Orf6, and the dehydratase domains and well as other PKS domains. ACP domains have been expressed with and without the phosphopantetheine modification by co‐expression with a phosphopantetheine transferase. The results from this work will facilitate the mechanistic understanding of marine biosynthetic machineries and will allow the harnessing of genes of marine origin for the production of new natural product with therapeutic potential. This work was founded by the MBRS‐RISE Program of the University of Puerto Rico Medical Sciences Campus, Grant R25GM061838.