Information propagation through enzyme-free catalytic templating of DNA dimerization with weak product inhibition

Information propagation by sequence-specific, template-catalysed molecular assembly is a key process facilitating life's biochemical complexity, yielding thousands of sequence-defined proteins from only 20 distinct building blocks. However, exploitation of catalytic templating is rare in non-biological contexts, particularly in enzyme-free environments, where even the template-catalysed formation of dimers is challenging. Typically, product inhibition-the tendency of products to bind to templates more strongly than individual monomers-prevents catalytic turnover. Here we present a rationally designed enzyme-free system in which a DNA template catalyses, with weak product inhibition, the production of sequence-specific DNA dimers. We demonstrate selective templating of nine different dimers with high specificity and catalytic turnover, then we show that the products can participate in downstream reactions, and finally that the dimerization can be coupled to covalent bond formation. Most importantly, our mechanism demonstrates a design principle for constructing synthetic molecular templating systems, a first step towards applying this powerful motif in non-biological contexts to construct many complex molecules and materials from a small number of building blocks.