Figure 7.

Scheme showing the biosynthetic route to nisin A. For clarity, the process is shown as first completion of dehydration and then cyclization, but this is not necessarily the case. The timing of the different PTMs installed on the NisA precursor peptide is discussed in the text. The FNLD motif in the leader peptide (bolded and underlined) is conserved in other class I lanthipeptide leader peptides and appears important in interactions with both NisB and NisC. The cyclization catalyzed by NisC is reversible as shown by experiments involving resubjection of mNisA to the cyclization conditions (section 2.3).