Figure 2.

Definitions of NACs for P450-catalyzed compactin (6S)-hydroxylation. The symbol d denotes the distance between the reactive oxygen and the hydrogen (pro-S is shown) that is replaced by a hydroxyl group. θ₁ is the angle between the iron, the reactive oxygen, and the hydrogen. θ₂ is the angle between the reactive oxygen, the carbon, and the hydrogen of the substrate. NAC criteria were: d ≤ 2.7 Å; 100° < θ₁ < 140°; and θ₂ > 140°. The same criteria were used for pro-R NACs.