High divergence of the precursor peptides in combinatorial lanthipeptide biosynthesis

Area of Science:

• Biochemistry
• Molecular Biology
• Natural Product Chemistry

Background:

• Lanthipeptides are polycyclic peptides synthesized ribosomally and modified post-translationally.
• Prochlorosin synthetase (ProcM) from Prochlorococcus MIT9313 uniquely produces diverse prochlorosins from multiple precursor peptides.
• These natural products are found across diverse species with varied biosynthetic systems and activities.

Purpose of the Study:

• To investigate the substrate scope and evolutionary origins of leader peptides in ProcM-like enzymes.
• To determine the functional importance of N-terminal sequences in precursor peptides for enzymatic modification.
• To explore the potential of genome mining and bioengineering for discovering novel lanthipeptides.

Main Methods:

• Enzyme activity assays using ProcM-like enzymes and diverse precursor peptides.
• Bioinformatic analysis of leader peptide sequences and evolutionary origins.
• Site-directed mutagenesis to assess the role of N-terminal regions in precursor peptides.

Main Results:

• ProcM-like enzymes from various bacteria demonstrate broad substrate specificity for diverse precursor peptides.
• Leader peptides originate from different evolutionary backgrounds, indicating enzyme-specific combinatorial biosynthesis.
• N-terminal truncations of precursor peptides are tolerated, with approximately two-thirds of the N-terminal sequence being non-essential for ProcM activity.

Conclusions:

• ProcM-like enzymes represent a versatile platform for natural combinatorial biosynthesis of lanthipeptides.
• The findings suggest that combinatorial biosynthesis is linked to the enzyme's machinery rather than specific leader peptides.
• This study underscores the potential for discovering new lanthipeptides through genome mining and bioengineering approaches.