Saturation mutagenesis of selected residues of the α‐peptide of the lantibiotic lacticin 3147 yields a derivative with enhanced antimicrobial activity

Abstract

SummaryThe lantibiotic lacticin 3147 consists of two ribosomally synthesized and post-translationally modified antimicrobial peptides, Ltnα and Ltnβ, which act synergistically against a wide range of Gram-positive microorganisms. We performed saturation mutagenesis of specific residues of Ltnα to determine their functional importance. The results establish that Ltnα is more tolerant to change than previously suggested by alanine scanning mutagenesis. One substitution, LtnαH23S, was identified which improved the specific activity of lacticin 3147 against one pathogenic strain, Staphylococcus aureus NCDO1499. This represents the first occasion upon which the activity of a two peptide lantibiotic has been enhanced through bioengineering.Funding Information Work in the authors' laboratory is supported by the Irish Government under the National Development Plan; by the Irish Research Council for Science Engineering and Technology (IRCSET); by Enterprise Ireland; and by Science Foundation Ireland (SFI), through the Alimentary Pharmabiotic Centre (APC) at University College Cork, Ireland, which is supported by the SFI-funded Centre for Science, Engineering and Technology (SFI-CSET) and provided P.D.C., C.H and R.P.R. with SFI Principal Investigator funding.

Lichenicidin rational site‐directed mutagenesis library: A tool to generate bioengineered lantibiotics

“…For detailed characterization and biosynthetic pathways of lantibiotics, the readers are referred to Arnison et al (); Barbosa, Caetano, and Mendo (); and Repka, Chekan, Nair, and van der Donk (). Considering their synthesis, and also from a biotechnological perspective, lantibiotics are relatively easy to modify through mutagenesis approaches, as described by many authors (Appleyard et al, ; Boakes et al, ; Chen et al, ; Cotter, ; Cotter et al, ; Deegan et al, ; Field, Connor, Cotter, Hill, & Ross, ; Field et al, ; Healy et al, ; Knerr & van der Donk, ). This approach was employed to reveal information on structure–function relationship, to improve antimicrobial and pharmacological properties of lantibiotics and also for the rational design of these peptides.…”

“…The same was also reported for mutacin 1140, allowing to determine the ideal distance between A and B rings and also the size of the A ring (Chen et al, ). With regard to lacticin 3147, along with the generation of improved variants (Deegan et al, ; Field et al, ), charged amino acids seem to play a significant role on bioactivity (Deegan et al, ).…”

Engineering Unnatural Variants of Plantazolicin through Codon Reprogramming

“…Similar approaches have also been applied to the study of other lanthipeptides, including lacticin 3147 (12, 13), mersacidin (14), lichenicidin (15), and actagardine A (16). This strategy has also garnered recent attention outside of the lanthipeptide family, where it has been successfully employed to engineer novel variants and explore the substrate requirements for the precursor peptides of several thiopeptides (17–21), cyanobactins (22) and microcin J25 (23).…”

Multipronged approach for engineering novel peptide analogues of existing lantibiotics

“…Producing enhanced variants of two-component lantibiotics is much more challenging given that two lantibiotic peptides work together in synergy. Recently, a single variant in lacticin 3147 Ltna in which the histidine at position 23 was substituted with a serine had an increase in activity against a pathogenic strain of S. aureus [65].…”

“…Class I lantibiotics; mutacin 1140 and nisin[40,47,48,[53][54][55][56], B. Class II lantibiotics; nukacin-ISK1, mersacidin and actagardine[39,[60][61][62], C. Two-component lantibiotics, lacticin 3147 --Ltna and Lacticin 3147 --Ltnb[64,65]. Unusual amino acids are labeled as such: Dha: 2,3-didehydroalanine, Dhb, 2,3-didehydrobutyrine, Ala-S-Ala: lanthionine ring, Ala-S-Abu: (methyl)lanthionine ring, D-Ala: D-alanine, 2-ob: 2-oxobutyrate.…”