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bioRxiv · 10.1101/2021.03.09.434688

Molecular mechanism underlying substrate recognition of the peptide macrocyclase PsnB

Song, I.·Kim, Y.·Yu, J.·Go, S. Y.·Lee, H. G.·Song, W. J.·Kim, S.
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Abstract

Graspetides, also known as omega-ester-containing peptides (OEPs), are a family of ribosomally synthesized and post-translationally modified peptides (RiPPs) bearing side-to-side macrolactone or macrolactam linkages. Here we present molecular details of the precursor recognition of the macrocyclase enzyme PsnB in the biosynthesis of plesiocin, a Group 2 graspetide. Biochemical analysis revealed that, in contrast to other RiPPs, the core region of the plesiocin precursor peptide noticeably enhanced the enzyme-precursor interaction via the conserved glutamates. We obtained four crystal structures of symmetric or asymmetric PsnB dimers including those with a bound core peptide and a nucleotide, and suggest that the highly conserved Arg213 at the enzyme active site specifically recognizes a ring-forming acidic residue and escorts it to ATP for phosphorylation. Collectively, this study provides insights into the mechanism underlying substrate recognition in the graspetide biosynthesis, and lays a foundation for engineering new variants.

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Song, I., Kim, Y., Yu, J., Go, S. Y., Lee, H. G., Song, W. J., Kim, S.. 2021-03-10. Molecular mechanism underlying substrate recognition of the peptide macrocyclase PsnB. https://doi.org/10.1101/2021.03.09.434688

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