In the August 2009 edition of Nature Biotechnology, SynBERC researcher John Dueber and company show how they engineered synthetic protein scaffolds to recruit metabolic enzymes in a manner that greatly improves production of an end-product while lowering the overall metabolic load on the chassis organism. The principle behind such metabolic pipelines is simple: Assemble enzyme complexes so that active sites are close together in order to prevent loss of intermediates and competition from other pathways. Such an arrangement also concentrates metabolites in a small area while keeping total cellular levels low, which is important for toxic or unstable intermediates.

The researchers created stable intracellular scaffolds, or pipelines, to which successive pathway enzymes dock via small peptide ligands. The scaffolds used three highly specific and modular metazoan docking domains in a strategy that builds on previous work by SynBERC researchers Dueber, Wendell Lim, and Ethan Mirsky in constructing highly sensitive signaling switches (Dueber et al, Nat. Biotechnol. 2007). The scaffold was also shown to increase production of a structurally unrelated compound (glucaric acid) in the separate lab of SynBERC investigator Kristala Jones Prather.  In an accompanying commentary, Matthew DeLisa and Robert Conrado at Cornell University call the study “the first use of directed assembly of enzyme complexes for optimizing chemical production in microorganisms” and a useful complement to existing metabolic engineering techniques.

Dueber, J.E. et al. Synthetic protein scaffolds provide modular control over metabolic flux. Nat Biotechnol. 2009 Aug;27(8):753-9.