2D Enzyme Cascade Network with Efficient Substrate Channeling by Swinging Arms

Abstract

In living cells, compartmentalized or membrane-associated enzymes are often assembled into large networks to cooperatively catalyze cascade reaction pathways essential for cellular metabolism. Here, we report the assembly of an artificial 2D enzyme network of two cascade enzymes-glucose-6-phosphate dehydrogenase (G6PDH) and lactate dehydrogenase (LDH)-on a wireframe DNA origami template. Swinging arms were used to facilitate the transport of the redox intermediate of NAD⁺ /NADH between enzyme pairs on the array. The assemblies of 2D enzyme networks were characterized by gel electrophoresis and visualized by atomic force microscopy (AFM). The spatial arrangements of multiple enzyme pairs were optimized to facilitate efficient substrate channeling by exploiting the programmability of DNA origami to manipulate the key parameters of swinging arm length and stoichiometry. Compared with a single enzyme pair, the 2D organized enzyme systems exhibited higher reaction efficiency due to the promoted transfer of intermediates within the network.

Keywords: DNA nanotechnology; enzyme cascade; redox intermediate; scaffold.