AUTHOR=Bartholomae Maike , Baumann Tobias , Nickling Jessica H. , Peterhoff David , Wagner Ralf , Budisa Nediljko , Kuipers Oscar P. 

TITLE=Expanding the Genetic Code of Lactococcus lactis and Escherichia coli to Incorporate Non-canonical Amino Acids for Production of Modified Lantibiotics

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.00657

DOI=10.3389/fmicb.2018.00657

ISSN=1664-302X

ABSTRACT=<p>The incorporation of non-canonical amino acids (ncAAs) into ribosomally synthesized and post-translationally modified peptides, e.g., nisin from the Gram-positive bacterium <italic>Lactococcus lactis</italic>, bears great potential to expand the chemical space of various antimicrobials. The ncAA <italic>N</italic><sub>ε</sub>-Boc-<sc>L</sc>-lysine (BocK) was chosen for incorporation into nisin using the archaeal pyrrolysyl-tRNA synthetase–tRNA<sup>Pyl</sup> pair to establish orthogonal translation in <italic>L. lactis</italic> for read-through of in-frame amber stop codons. In parallel, recombinant nisin production and orthogonal translation were combined in <italic>Escherichia coli</italic> 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 <italic>E. coli</italic> and <italic>L. lactis</italic> presents a promising tool to create new-to-nature nisin derivatives.</p>