Skip to main content
. 2021 Sep 30;10:e71959. doi: 10.7554/eLife.71959

Figure 2. Assay of 2,3-dimethyl-[1,4]naphthohydroquinone (DMWH2:O2) oxidoreductase activity of CIII2CIV2.

(A) An oxygen reduction assay shows that autoxidation of DMWH2, blue curve, is decreased by the presence of 500 nM bovine superoxide dismutase (SOD), orange curve. Measurement of oxygen reduction by CIII2CIV2 in the presence of bovine SOD, green curve, allows calculation of CIII2CIV2 activity. (B) Structure of CIII2CIV2 inhibitor telacebec (Q203). (C) Titration of CIII2CIV2 (60 nM) with telacebec shows an IC50 of 53 ± 19 nM (± s.d., n = 3 independent titrations) with 100 µM DMWH2.

Figure 2.

Figure 2—figure supplement 1. Structural and kinetic comparison of menaquinone and analogues.

Figure 2—figure supplement 1.

Oxidized menaquinone (A), menadione (2-methyl-[1,4]naphthoquinone) (B), and DMW (2,3-dimethyl-[1,4]naphthoquinone) (C) are shown. (D) An overlay of oxygen reduction assays shows that the rate of autoxidation for menadiol (2-dimethyl-[1,4]naphthohydroquinone) blue curve, is larger than for DMWH2 (2,3-dimethyl-[1,4]naphthohydroquinone) red curve, and both autoxidation rates decrease in the presence of 500 nM bovine superoxide dismutase (SOD) orange and purple curves. Measurement of oxygen reduction by CIII2CIV2 in the presence of bovine SOD shows that CIII2CIV2 activity is greater with DMWH2 green curve, than with menadiol brown curve.