Make the switch: The three-enzyme cassette MarG/H/I is responsible for stereospecific biosynthesis of β-methyltryptophan from L-tryptophan (1). MarG/I convert 1 into (2S,3R)-β-methyltryptophan, while MarG/I combined with MarH convert 1 into (2S,3S)-β-methyltryptophan. MarH serves as a stereochemical switch by catalyzing the stereoinversion of the β-stereocenter.

Wahlweise: Die Drei‐Enzyme‐Kassette MarG/H/I steuert die stereospezifische Biosynthese von β‐Methyltryptophan aus L‐Tryptophan (1). MarG/I wandelt 1 in (2S,3R)‐β‐Methyltryptophan um, während MarG/I in Kombination mit MarH aus 1 das (2S,3S)‐β‐Methyltryptophan erzeugt. MarH dient als stereochemischer Schalter, indem es die Inversion des β‐Stereozentrums katalysiert.