During QM/MM geometry optimizations, the QM region was treated using the hybrid UB3LYP functional with two basis sets, B1 and B2, where B1 stands for def2-SVP and B2 stands for def2-TZVP. The B1 basis set was used for geometry optimization, potential energy surface scanning, and frequency calculations. The energies were further corrected with the Grimme dispersion correction. All of the QM/MM transition states were located by relaxed potential energy surface (PES) scans followed by full TS optimizations using the P-RFO optimizer implemented in the HDLC code. The energies were further corrected with the large all-electron basis set, designated as def2-TZVP. The zero-point energies (ZPE) were calculated for all the species and the corresponding final energies were reported as UB3LYP/B2-D3+ZPE. Since s=1/2 (doublet) and s=3/2 (quartet) spin state of Cpd I generally exhibit similar reactivities in CYP450 enzymes. For the sake of comparison to the already reported mechanistic studies, we have performed the calculation in the same spin state i.e., s=1/2 (doublet) used in earlier studies.