The pearl jubilee of microcin J25: thirty years of research on an exceptional lasso peptide

Abstract

A lasso peptide takes the spotlight. This review summarizes 30 years of research on microcin J25 and covers everything from its discovery in 1992, through the study of its antimicrobial activity, to its most recent application in bioengineering.

Merging Flow Synthesis and Enzymatic Maturation to Expand the Chemical Space of Lasso Peptides

“…The biosynthetic production of MccJ25 requires the simultaneous presence of the leader peptidase (McjB) and lasso cyclase (McjC) (Figure A) . To date, their molecular mechanism remains cryptic due to difficulties in obtaining enzymes in sufficient quantity and quality . To further investigate enzyme promiscuity, we set out to develop a more robust expression protocol for McjB (Figure B) and McjC (Figure C).…”

“…The technology of flow-based chemical synthesis of precursor peptides could be further expanded to other in vitro lasso peptide maturation systems , or cell-free biosynthesis procedures, as shown for fuscanodin. With over 80 discovered lasso peptides and more to be identified by genome mining, , there is significant room for future exploration. The combination of reliable chemical peptide synthesis and reproducible enzymatic expression thus adds lasso peptides to the RiPP enzyme toolbox.…”

“…Lasso and branchedcyclic (unthreaded) peptide products were distinguished with LC-IM-MS measurements by comparing the mobilograms and the smallest collision cross section (CCS) peak (Figure 3C), as previously established for lasso peptides. 11,12,36 In addition, threadedness could be evaluated by thermolysin digestion combined with MS analysis, as MccJ25 cleavage forms [2]rotaxanes, owing to the steric plugs Phe-19 and Tyr-20 (Figure 3D), while branched-cyclic peptides are cleaved into separate, not interlocked peptides. 37 For control samples, we used biologically produced MccJ25 and its chemically synthesized branched-cyclic analogue, which was obtained via on-resin cyclization.…”

“…Chemical synthesis would enable the incorporation of ncAAs; however, unlike other cyclic and conformationally constrained peptides (Figure 1A), 7−10 the bioactive lasso peptide microcin J25 (MccJ25) has resisted numerous synthesis attempts. 11,12 Nevertheless, biological methods were explored to derivatize MccJ25 with canonical amino acids to alter its activity and study its biogenesis. 13−16 Biosynthetically, the lasso structure of MccJ25 (21 AA) is achieved through enzymatic maturation of the precursor peptide McjA (57 AA) by two enzymes: McjB removes the leader sequence, and McjC, a lasso cyclase, forms the isopeptide linkage between the N-terminal amine and the Glu-8 side chain.…”

Natural products from the human microbiome: an emergent frontier in organic synthesis and drug discovery

“…In addition, lasso peptides microcin J25 ( 134 ), acinetodin, klebsidin, etc ., with potent antibiotic activities against Gram −ve pathogens, are highly challenging synthetic targets due to their unique catenane-like structures (lariat protoknot) where the C-terminal ends are threaded (dotted line) through a peptide macrocycle. 92,93…”