New pathway for antimicrobial peptides

Researchers in the Princeton University Department of Chemistry have discovered a new multi-step pathway through which bacteria found in the mammalian gut produce antimicrobial peptides.

The newly identified biosynthetic pathway transforms a biologically inert peptide into structurally complex antibiotics, which they call enteropeptins. Enteropeptins are a class of ribosomally synthesized peptide natural products, referred to as RiPPs.

The core structure of these products is synthesized by the ribosome, which is limited to the 20 canonical amino acids. The Mo Lab discovered and characterized new metalloenzymes capable of converting arginine, a canonical amino acid, into N-methylornithine, a noncanonical amino acid, within enteropeptin.

This is the first report of a RiPP natural product containing this unusual amino acid. The discovery was made by the lab of Professor Mohammad Seyedsayamdost.

The lab’s paper, “Biosynthesis-guided discovery reveals enteropeptins as alternative sactipeptides containing N-methylornithine,” was published last month in Nature Chemistry.

Kenzie Clark, first author on the paper and a former graduate student in the Mo Lab, explained the core discoveries.

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