Characterization of roseocin a novel recombinant two component lantibiotic produced from E coli BL21 DE3

Abstract

Amid the rapid spread of antimicrobial resistance (AMR), lantibiotics have emerged as a new hope due to their ability to kill common antimicrobial-resistant Gram-positive strains, like methicillin-resistant S. aureus (MRSA) and vancomycin-resistant E. faecium (VRE). Roseocin, discovered in our lab earlier, is one such example that was characterized further. Roseocin, obtained by Proteinase K based in vitro reconstitution, showed efficacy against these drug- resistant strains in micromolar concentrations, demonstrating its potential against the pathogens. Also, an insight into its mode of action was obtained, which established roseocin as an antimicrobial, having bactericidal activity through pore formation. Believing evolution for a best variant is an ongoing phenomenon in nature, a phylogeny-guided study was done to discover homologs of roseocin which showed the unique characteristic features of roseocin family peptides evolution, identifying the conserved and a similar motif in both the peptides. The phylogenetic study also supported the predicted ring topology pattern of RosA1and#946; obtained through MALDI-TOF tandem MS study. Thus, combining the observations of tandem MS and phylogeny-guided approach, structure of the RosA2and#945; is proposed as a globular-shaped peptide, containing four (methyl) lanthionine rings and one indispensable disulfide bond. newline