Dihydrophenylalanine: A Prephenate-Derived Photorhabdus luminescens Antibiotic and Intermediate in Dihydrostilbene Biosynthesis

Abstract

Summary 2,5-Dihydrophenylalanine (H2Phe) is a multi-potent non-proteinogenic amino acid produced by various Actinobacteria and Gammaproteobacteria. While the metabolite was discovered over forty years ago, details of its biosynthesis have remained largely unknown. We show here that L-H2Phe is a secreted metabolite in Photorhabdus luminescens cultures and a precursor of a recently described 2,5-dihydrostilbene. Bioinformatic analysis suggested a candidate gene cluster for the processing of prephenate to H2Phe, and gene knockouts validated that three adjacent genes plu3042-3044 were required for H2Phe production. Biochemical experiments validated Plu3043 as a non-aromatizing prephenate decarboxylase generating an endocyclic dihydro-hydyroxyphenylpyruvate. Plu3042 acted next to transaminate the Plu3043 product, precluding spontaneous exocyclic double bond isomerization and yielding 2,5-dihydrotyrosine. The enzymatic products most plausibly on path to H2Phe illustrate the versatile metabolic rerouting of prephenate from aromatic amino acid synthesis to antibiotic synthesis.

Comprehensive database of secondary metabolites from cyanobacteria

“…For example, in the case of microcystins with fully established stereochemistries, position-2 and -4 have always been found to contain L-amino acids, with D-amino acids at position-1, 3 and -6. Similarly, the stereochemistry of di-and tetrahydrotyrosine in microcystins was assumed to be that established in other bacteria by Walsh et al, 9,10 and this will if necessary be amended if found to be incorrect. We include some additional entries that are known metabolites, oxidation products, or (semi)synthetic and indicate them as such in the note section.…”

Nonproteinogenic Amino Acid Building Blocks for Nonribosomal Peptide and Hybrid Polyketide Scaffolds

“…[184] Another amino acid of particular interest in the natural dienoic dihydro amino acid category is gabaculine ( 56 , Figure 22D). [185] Its biosynthesis is not yet resolved but its mechanism of action with certain PLP-dependent enzymes has been studied.…”

Nichtproteinogene Aminosäurebausteine für Peptidgerüste aus nichtribosomalen Peptiden und hybriden Polyketiden

“…[183] 2,5-Dihydrophenylalanin (55, Abbildung 22 D) ist eine andere g,d-ungesättigte Aminosäure, die als bakterieller Antimetabolit den Phe-Stoffwechsel stçren kann. [184] Eine weitere interessante Aminosäure aus der Gruppe natürlicher Diendihydroaminosäuren ist Gabaculin (56, Abbildung 22 D). [185] Die Biosynthese ist noch nicht aufgeklärt, aber der Reaktionsmechanismus mit einigen PLP-abhängigen Enzymen wurde untersucht.…”