Fig. 7: Conformational dynamics of PneKC and PneA during peptide binding: towards a working model for lanthipeptide modification by PneKC.

a Steps in the binding of PneA to PneKC, which show a progression from the pre-binding state, in which loops at the primary groove are largely disordered, to the LP-bound state, in which the PneA-binding loops become ordered while PneA LP exists in an extended conformation, to the fully-recognized state, in which all the PneA-binding loops are ordered and PneA LP adopts a helical conformation that is sealed underneath the gate loop. b A working model for initial PneA recognition and subsequent modification by the PneKC dimer based on a negative cooperativity mechanism.