Biomimetic S-Adenosylmethionine Regeneration Starting from Different Byproducts Enables Biocatalytic Alkylation with Radical SAM Enzymes

Abstract

AbstractS-Adenosylmethionine (SAM) is an enzyme cofactor involved in methylation, aminopropyl transfer, and radical reactions. This versatility renders SAM-dependent enzymes of great interest in biocatalysis. The usage of SAM analogues adds to this diversity. However, high cost and instability of the cofactor impedes the investigation and usage of these enzymes. While SAM regeneration protocols from the methyltransferase (MT) byproductS-adenosylhomocysteine are available, aminopropyl transferases and radical SAM enzymes are not covered. Here, we report an efficient one-pot system to supply or regenerate SAM and SAM analogues for all three enzyme classes. The system’s flexibility is showcased by the transfer of an ethyl group with a cobalamin-dependent radical SAM MT usingS-adenosylethionine as a cofactor. This shows the potential of SAM (analogue) supply and regeneration for the application of diverse chemistry, as well as for mechanistic studies using cofactor analogues.