Discovery and Characterization of a Class IV Lanthipeptide with a Nonoverlapping Ring Pattern

Area of Science:

• Biochemistry
• Molecular Biology
• Microbiology

Background:

• Lanthipeptides are a major class of ribosomally synthesized and post-translationally modified peptides (RiPPs).
• They are categorized into four subfamilies based on lanthipeptide synthetase characteristics.
• Class IV lanthipeptides are rare, with limited known structural diversity.

Purpose of the Study:

• To identify and characterize novel class IV lanthipeptides.
• To elucidate the biosynthetic pathway and maturation mechanism of a newly discovered class IV lanthipeptide.
• To explore the potential for discovering new lanthipeptides with unique structural features and biological activities.

Main Methods:

• Bioinformatic analysis to identify uncharacterized lanthipeptide groups.
• Heterologous expression of a representative pathway from *Streptomyces* sp. NRRL S-1022 in *Escherichia coli*.
• Biochemical assays to investigate the biosynthetic mechanism and peptidase activity.

Main Results:

• Identification of a novel group of class IV lanthipeptides.
• Generation of a lanthipeptide with two non-overlapping rings, a previously unreported feature for class IV lanthipeptides.
• Demonstration of parallel dehydration and cyclization during biosynthesis.
• Identification of two aminopeptidases with dual endopeptidase/aminopeptidase activity responsible for peptide maturation.

Conclusions:

• This study expands the structural diversity of class IV lanthipeptides.
• The findings reveal a novel biosynthetic mechanism involving parallel modification pathways.
• The identified peptidases provide insight into the maturation of class IV lanthipeptides, opening avenues for discovering new bioactive RiPPs.