TRISAFA · Transport of Reaction Intermediates in the Stepwise Assembly of Fatty Acids

Fatty acids are essential metabolites used in biological cell wall formation, energy storage, and signal transduction. Fatty acid synthesis is carried out in an iterative sequence of reactions, conserved across all species. Yet different organisms have developed different solutions, the most impressive is the fungal fatty acid synthase (FAS). The 2.6 MDa molecular complex integrates all enzymatic functions required for the stepwise assembly of fatty acids. Its architecture is reminiscent of a chemical nanofactory: The enzymatic domains face the lumen of the barrel-shaped complex, where nascent fatty acids are transferred between active sites by an integral acyl carrier protein (ACP). The function of the fungal FAS has long been in focus of research, not only due to its elaborate architecture but also because it is ideally suited as a platform for synthetic biology. Fatty acid derivatives are ideal precursors to produce biofuels or fine chemicals; and fungi are well adapted for industrial applications.Advances in experimental structural biology have established a framework for the progression of the synthesis cycle. However, the driving element is the transport of reaction intermediates by the ACP which is inherently dynamics. Thus, structures alone are insufficient for a mechanistic understanding of the fungal FAS function. TRISAFA aims to close this knowledge gap by integrating advances in structural biology with molecular dynamics simulations to resolve the pace and regulation of the transport process in atomistic detail. This approach will address three hitherto unanswered questions: First, how are the transport dynamics coupled to the conformational dynamics of the FAS? Second, how is the pace of the transport regulated? And finally, what factors determine termination of the fatty acid synthesis cycle. Ultimately, this project will yield a complete model for the progression of fatty acid synthesis, pivotal to their exploitation for biotechnological applications