Genes Involved in Biosynthesis of Paenibacillin, a Novel Antimicrobial Peptide

Introduction: Lantibiotics are ribosomally synthesized lanthionine-containing antimicrobial peptides produced by Gram-positive bacteria. Paenibacillin, a lantibiotic from Paenibacillus polymyxa OSY-DF with an unusual N-terminal acetyl group, shows potent activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus, Listeria monocytogenes and Mycobacterium smegmatis.

Purpose: This study describes the biosynthesis of paenibacillin and its N-terminal acetylation.

Methods: The structural gene of paenibacillin was identified by polymerase chain reaction; the complete biosynthetic gene cluster was determined by whole-genome sequencing using Illumina’s next generation technology. De novo assembly of the P. polymyxa OSY-DF draft genome was performed using CLC Genomics Workbench software.

Results: In the bacterial genome, a 12.3-kb DNA fragment, consisting of 11 open reading frames (ORFs), is involved in paenibacillin production, modification, immunity, regulation and transportation. One of the ORFs (paenN), which encodes a protein with high sequence similarity to F-pilin acetylase, may be responsible for the N-terminal acetylation of alanine during paenibacillin biosynthesis. Unlike other lantibiotics, an agr-like quorum sensing system encoded by the biosynthetic gene cluster may regulate the production of paenibacillin in P. polymyxa OSY-DF.

Significance: These findings elucidate the pathway of paenibacillin biosynthesis and pave the way to produce paenibacillin variants through genetic manipulation. The study also reports a putative acetylase responsible for peptide N-terminal acetylation, which is extremely rare in bacteria.