Mining for Novel Tryptophanase A: Extremophilic Organisms Ardenticatena maritima and Haloarcula japonica as Alternatives to E. coli in the Synthesis of Tryptophan Analogues

Tryptophan (Trp) analogues are a subgroup of noncanonical amino acids (ncAAs), which are increasingly valued in the chemical and pharmaceutical industries. Biocatalytic approaches to the preparation of enantiopure Trp analogues offer highly sustainable pathways with unrivalled stereoselectivity and efficiency. In this study, we characterized two novel TnaA enzymes from the extremophilic bacterium Ardenticatena maritima and archaeon Haloarcula japonica which, in comparison to the well-established Escherichia coli tryptophanase (EcTnaA), exhibited enhanced stability under extreme physicochemical conditions, making them promising candidates for biocatalytic synthesis of indole-containing amino acids.