antimicrobial-peptides-produced-selective-pressure-incorporation-non

Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids

Nature has a variety of possibilities to create new protein functions by modifying the sequence of the individual amino acid building blocks. However, all ...

University of Groningen

Post-translationally modified peptides commonly display antimicrobial activity, but can also aid the development of bacterial colonies, giving a competitive advantage in the ecological niche. The production of post-translationally modified peptides by bacteria is a complex and energetically costly process that is strictly orchestrated in the cell. The onset of peptide production is linked to the different enzymes that take part during maturation, the transporters and the immunity determinants (if required). Thus, the population can make optimal use of available resources and obtain the benefits of production at an advantageous moment during growth, avoiding toxicity to itself. The timing and level of expression of the different operons is controlled by diverse (complex) regulatory pathways in response to environmental changes, stress or master regulators during specific growth transition phases. In this review, we highlight the basic principles and mechanisms of regulation of expression of post-translationally modified peptides and the relationship with the overall culture developmental processes and/or cellular differentiation. We also discuss the biotechnological consequences derived from the understanding of regulatory networks involved in the biosynthesis of these natural products.

Major gene-regulatory mechanisms operating in ribosomally synthesized and post-translationally modified peptide (RiPP) biosynthesis.

The incorporation of non-canonical amino acids (ncAAs) into ribosomally synthesized and post-translationally modified peptides, e.g., nisin from the Gram-positive bacterium , bears great potential to expand the chemical space of various antimicrobials. The ncAA -Boc-L-lysine (BocK) was chosen for incorporation into nisin using the archaeal pyrrolysyl-tRNA synthetase-tRNA pair to establish orthogonal translation in  for read-through of in-frame amber stop codons. In parallel, recombinant nisin production and orthogonal translation were combined in  cells. Both organisms synthesized bioactive nisin(BocK) variants. Screening of a nisin amber codon library revealed suitable sites for ncAA incorporation and two variants displayed high antimicrobial activity. Orthogonal translation in  and  presents a promising tool to create new-to-nature nisin derivatives.

Maike Bartholomae

Molecular Genetics Group,
Groningen Biomolecular Sciences and Biotechnology Institute,
Department of Molecular Genetics,
Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Department of Molecular Genetics

University of Groningen

Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids