Fig. 3: Trp-mediated ROS generation under blue light irradiation.
From: Hidden route of protein damage through oxygen-confined photooxidation
a O2-trapping subareas with relatively tight O2 binding (see “Methods”). In each subarea, the colored residues represent those whose atoms are located within 3.5 Å from O2 atoms during the binding periods. b Absorption spectra of residue-O2 pairs in O2-trapping subarea 1 from density functional theory (DFT) calculations. The residues are denoted as 3-letter code. The residue numbers indicate those following the signal peptide sequence. The inset shows the Trp62-O2 structure with the maximum oscillator strength. c Relative energy diagram for singlet and triplet states of Trp62-O2 pair. The molecular orbitals are shown for the transition from T0 to TCT state. d Molecular orbital diagrams and overall pathway for 1O2 generation. e ABDA assay for 1O2 detection (n = 3 independent samples for each condition; mean ± SD). The gray-shaded box indicates the region of absorbance for amino acids other than Trp. f Electron paramagnetic resonance (EPR) measurement using TEMP for 1O2 detection. The EPR spectra are averaged from triplicates for each condition and are expressed in arbitrary unit (a.u.). The inset shows the EPR intensity for each condition (n = 3 independent samples for each condition; mean ± SD). One-way ANOVA with post hoc Tukey HSD test (***p = 0.0004, **p = 0.007, and *p = 0.03). g DHR123 assay for the detection of type I reactive oxygen species (ROS), such as O2•–, H2O2, and •OH (n = 3 independent samples for each condition; mean ± SD). The gray-shaded box indicates the region of absorbance for amino acids other than Trp. h HPF assay which is more specific to •OH (n = 3 independent samples for each condition; mean ± SD). Relevant source data are provided as a Source Data file.
