Fig. 1

Biosynthesis of the two-component lantibiotic roseocin. A Roseocin is constituted of two precursor peptides, RosA1β and RosA2α, which are post-translationally modified by RosM in two steps (dehydration followed by cyclization). This is followed by leader removal in vitro using commercially available proteases like endoproteinase GluC or proteinase K (Singh et al. 2020). The ring topology of roseocin peptides is supported by mass spectrometry and bioinformatic analysis as per the current study. B Common PTMs in the biosynthesis of lanthipeptide involves the dehydration of serine and threonine amino acid residues to 2,3-dehydroalanine (Dha) and 2,3-dehydrobutyrine (Dhb), respectively. Michael-type addition of Cys to Dha leads to lanthionine (Lan), while addition to Dhb results in a methyllanthionine (MeLan) ring. Abu aminobutyrate, Ala Alanine, SIVR semi-in vitro reconstitution, HP Hypothetical Protein, RosTp dual function peptidase-domain containing transporter, RosF group of immunity proteins (in red colour), TR Transcriptional Regulator