Engineered Biosynthesis of β‐Alkyl Tryptophan Analogues

다국어 초록 (Multilingual Abstract)

Noncanonical amino acids (ncAAs) with dual stereocenters at the α and β positions are valuable precursors to natural products and therapeutics. Despite the potential applications of such bioactive β‐branched ncAAs, their availability is limited due to the inefficiency of the multistep methods used to prepare them. Herein we report a stereoselective biocatalytic synthesis of β‐branched tryptophan analogues using an engineered variant of Pyrococcus furiosus tryptophan synthase (PfTrpB), PfTrpB7E6. PfTrpB7E6 is the first biocatalyst to synthesize bulky β‐branched tryptophan analogues in a single step, with demonstrated access to 27 ncAAs. The molecular basis for the efficient catalysis and broad substrate tolerance of PfTrpB7E6 was explored through X‐ray crystallography and UV/Vis spectroscopy, which revealed that a combination of active‐site and remote mutations increase the abundance and persistence of a key reactive intermediate. PfTrpB7E6 provides an operationally simple and environmentally benign platform for the preparation of β‐branched tryptophan building blocks.
Zur Verzweigung gezüchtet: β‐Verzweigte Tryptophan‐Analoga sind nützliche bioaktive Moleküle, die jedoch nur schwer zu synthetisieren sind. Die Modifikation der β‐Untereinheit der Tryptophan‐Synthase (TrpB) mit dem Ziel, β‐verzweigte Tryptophan‐Analoga leicht verfügbar zu machen, führte zur TrpB‐Variante PfTrpB7E6, die die Synthese von 27 enantiomerenreinen β‐verzweigten Tryptophan‐Analoga in einem Schritt aus einfachen Ausgangsmaterialien katalysierte (siehe Bild).