Mutations near the cleavage site of enterocin NKR-5-3B prepeptide reveal new insights into its biosynthesis

Issue Date

4-2017

Abstract

Enterocin NKR-5-3B (Ent53B) is a 64-residue novel circular bacteriocin synthesized from an 87-residue prepeptide. Albeit through a still unknown mechanism, the EnkB1234 biosynthetic enzyme complex processes the prepeptide to yield its mature active, circular form. To gain insights into the key region/residue that plays a role in Ent53 maturation, several mutations near the cleavage site on the precursor peptide were generated. The interaction of the precursor peptide and EnkB1234 appeared to be hydrophobic in nature. At the Leu1 position, only mutations with helix structure-promoting hydrophobic residues (Ala, Ile, Val or Phe) were able to yield the mature Ent53B derivative. In this study, we also highlight the possible conformation-stabilizing role of the Ent53B leader peptide on the precursor peptide for its interaction with its biosynthetic enzyme complex. Any truncations of the leader peptide moiety interfered in the processing of the prepeptide. However, when propeptides of other circular bacteriocins (circularin A, leucocyclicin Q or lactocyclicin Q) were cloned at the C-terminus of the leader peptide, EnkB1234 could not process them to yield a mature bacteriocin. Taken together, these findings offer new perspectives in our understanding of the possible molecular mechanism of the biosynthesis of this circular bacteriocin. These new perspectives will help advance our current understanding to eventually elucidate circular bacteriocin biosynthesis. Understanding the biosynthetic mechanism of circular bacteriocins will materialize their application potential.

Source or Periodical Title

Microbiology (United Kingdom)

ISSN

1350-0872

Volume

163

Issue

4

Page

431-441

Document Type

Article

Physical Description

illustrations, tables, graphs

Language

English

Subject

Bacteriocin biosynthesis, Bacteriocin prepeptide, Bacteriocins, Circular bacteriocins, Lactic acid bacteria, Site-directed mutagenesis

Identifier

https://doi.org/10.1099/mic.0.000435

Digital Copy

yes

En – AGROVOC descriptors

Bacteriocin biosynthesis; Bacteriocin prepeptide; Bacteriocins; Circular bacteriocins; Lactic acid bacteria; Site-directed mutagenesis

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