Engineering Noncanonical Cofactors To Expand Cellular Functions

Synthetic biology often employs heterologous enzymatic reactions to reprogram cell metabolism or otherwise introduce novel functions. However, precise control of a particular metabolic pathway can be difficult to achieve because cofactors are shared with endogenous enzymes from a common pool. Recently, the use of noncanonical cofactors (NCCs) has emerged as a promising approach to bypass this problem by isolating desired reactions without the need for a physical barrier. Metabolic pathways that exclusively utilize NCCs can be insulated from the native machinery of the host cell, allowing them to function independently of the thermodynamic constraints imposed by sharing cofactors. This perspective explores the different types of NCCs and their synthesis methods, advancements in engineering NCC-dependent enzymes, and the potential applications of NCC-utilizing cells across various areas of synthetic biology.