Cytochrome P450_BltEnables Versatile Peptide Cyclisation to Generate Histidine‐ and Tyrosine‐Containing Crosslinked Tripeptide Building Blocks

Abstract

We report our investigation of the utility of peptide crosslinking cytochrome P450 enzymes from biarylitide biosynthesis to generate a range of cyclic tripeptides from simple synthons. The crosslinked tripeptides produced by this P450 include both tyrosine‐histidine (A−N−B) and tyrosine‐tryptophan (A−O−B) crosslinked tripeptides, the latter a rare example of a phenolic crosslink to an indole moiety. Tripeptides are easily isolated following proteolytic removal of the leader peptide and can incorporate a wide range of amino acids in the residue inside the crosslinked tripeptide. Given the utility of peptide crosslinks in important natural products and the synthetic challenge that these can represent, P450 enzymes have the potential to play roles as important tools in the generation of high‐value cyclic tripeptides for incorporation in synthesis, which can be yet further diversified using selective chemical techniques through specific handles contained within these tripeptides.

Biosynthesis of macrocyclic peptides with C-terminal β-amino-α-keto acid groups by three different metalloenzymes

“…Since P450s are not completely conserved in the BGCs we identified, the group of natural products deriving from these clusters are not part of the biarylitides. 24,73 Perhaps the most interesting modification we observed is catalyzed by BthHI, which are completely conserved in all orthologous BGCs. Previously reported MNIOs catalyze distinct chemical reactions on Cys residues.…”

“…Since P450s are not fully conserved among the BGCs we identified, the RiPPs described here are not classifiable as biarylitides. 21,82 Perhaps the most interesting modification observed was catalyzed by ApyHI (a member of the multinuclear non-heme iron-dependent oxidative enzyme superfamily, MNIO), which are universally conserved among the BGCs and thus considered class-defining. Previously characterized MNIOs catalyze distinct chemical reactions exclusively on Cys, although a very recent preprint suggests an MNIO catalyzes N-Cα bond cleavage of the penultimate Asn to generate a C-terminally amidated peptide in a methanobactin-like pathway.…”

“…Since P450s are not fully conserved among the BGCs we identified, the RiPPs described here are not classifiable as biarylitides. 21,82…”

Biosynthesis of Macrocyclic Peptides with C-Terminal β-Amino-α-keto Acid Groups by Three Different Metalloenzymes

“…Since P450s are not fully conserved among the BGCs we identified, the RiPPs described here are not classifiable as biarylitides. 21,82 Perhaps the most interesting modification observed was catalyzed by ApyHI (a member of the multinuclear non-heme iron-dependent oxidative enzyme superfamily, MNIO), which are universally conserved among apy BGCs and are thus considered class-defining. Previously characterized MNIOs catalyze distinct chemical reactions exclusively on Cys, although a very recent report describes an MNIO catalyzed N−Cα bond cleavage of an Asn to generate a C-terminal amide in a methanobactin-like pathway.…”

Bioinformatics-Guided Discovery of Biaryl-Tailored Lasso Peptides

“…Given the structural constraint installed by NopF/LopF, future work is warranted to reconstitute the enzymatic activity and substrate scope. [31] Lastly, the prediction that LopH is a founding member of a new Met S -methyltransferase family suggests that biochemical characterization of LopH may result in diversifying the existing methylation panel with a sulfonium PTM that can be harnessed in different bioconjugation contexts. [32]…”