Figure 2

Figure 2

Biliverdin specifically binds to MBP-NR2E3^LBD in vitro. (A) Visible spectra of biliverdin (5 μM) in the absence and in the presence of varying amounts of MBP-NR2E3^LBD. The blue peak shifts from 390 to 450 nm, while the red peak intensity diminishes upon binding to MBP-NR2E3^LBD. (B) Biliverdin stoichiometrically bound to MBP-NR2E3^LBD (filled circle). MBP-NR2E3^LBD R311Q variant (open circle) showed a weaker binding to biliverdin (5 μM). MBP-NR2E1^LBD (triangle) did not show any evidence of binding to biliverdin. Averages and standard deviations (n = 3) are presented. (C) Effect of MBP-NR2E3^LBD on visible spectra of (filled circle) bilirubin and (open circle) protoporphyrin IX (average and standard deviations, n = 3). (D) Effect of MBP-zebrafish NR2E3^LBD to the visible spectrum of biliverdin (average and standard deviations, n = 3). The concentration of biliverdin was identical to the one used in Fig. 2A, B.