Identification of a macrocyclic tambjamine natural product, tambjamine MYP1, from a marine bacterium that may enhance bioactivity by restraining bond rotation.

Prodiginines and tambjamines are related families of bioactive alkaloid natural products with pharmaceutical potential. Both compound families result from a convergent biosynthetic pathway ending in the condensation of a conserved bipyrrole core with a variable partner. This reaction is performed by unique condensation enzymes, and has the potential to be manipulated to produce new pyrrolic compounds. We have purified and reconstituted the in vitro activity of the condensation enzymes PigC and TamQ from Pseudoalteromonas sp., which are involved, respectively, in the prodiginine and tambjamine biosynthetic pathways. Kinetic analysis confirmed a Uni Uni Bi Uni ping‐pong reaction sequence with competitive and uncompetitive substrate inhibition for PigC and TamQ respectively. The kinetic parameters of each enzyme provide insight into their differing substrate scope, and suggest that TamQ may have evolved a wide substrate tolerance that can be used for the production of novel prodiginines and tambjamines.

We have reconstituted<i> </i>the <i>in vitro</i> activity of the purified condensation enzymes PigC and TamQ, from prodiginine and tambjamine pathways respectively. Upon analysis and comparison of their kinetic profiles, a ping-pong reaction sequence with substrate inhibition was identified for each condensation enzyme.