Fig. 4: Mechanisms of gluN2H3 and NAC installations onto the polyketide skeleton.
From: O-methyltransferase-like enzyme catalyzed diazo installation in polyketide biosynthesis
a Mechanistic alternatives for the coupling of gluN2H3 and polyketide intermediate. b HPLC analysis of the competition reactions: (i) DHR + AlpJ + AlpK + NADH; (ii) DHR + AlpJ + AlpK + NADH + gluN2H3; (iii) DHR + AlpJ + AlpK + NADH + NAC; (iv) DHR + AlpJ + AlpK + NADH + gluN2H3 + NAC; (v) DHR + AlpJ + AlpK + AlpH + NADH; (vi) DHR + AlpJ + AlpK + AlpH + NADH + gluN2H3; (vii) DHR + AlpJ + AlpK + AlpH + NADH + NAC; (viii) DHR + AlpJ + AlpK + AlpH + NADH + gluN2H3 + NAC. c HPLC analysis of the two-step reactions: (i) DHR + AlpJ + AlpK + AlpH + NADH, DHR was consumed with the formation of 1 and 6; (ii) DHR + AlpJ + AlpK + NADH, DHR was consumed with the formation of 1 and 6; (iii) gluN2H3 was added to reaction (i) when DHR was totally consumed; (iv) NAC was added to reaction (i) when DHR was totally consumed; (v) AlpH and gluN2H3 was added to reaction (ii) when DHR was totally consumed; (vi) AlpH and NAC was added to reaction (ii) when DHR was totally consumed; (vii) DHR + AlpJ + AlpK + AlpH + NADH + gluN2H3; (viii) DHR + AlpJ + AlpK + NADH + NAC.
