Fig. 4.

Active-site cavity volume representation of CYP2B35 (green) and CYP2B37 (magenta). (A) The active-site volume (495 A³) of the CYP2B35 structure is shown in cyan mesh. The important residue substitutions A363 and A367 that contribute to the enlarged binding cavity and two 4-CPI molecules (orange sticks) are also shown. (B) The CYP2B37 active-site volume including the second 4-CPI molecule calculated as 639 A³ and represented in black mesh. Active-site residue side chains with 5 Å from the 4-CPI molecules (blue lines) are shown as sticks. (C) Active-site cavity volume (469 A³) measured excluding the second 4-CPI molecule located at the periphery of the active site and the access channel. Residue side chains of V104, F206, I209, and L362 that contribute to the subcavities or pockets in the CYP2B37 structure are also shown. (D) Differences in the cavity volume between the upper half and the lower half of the active site in CYP2B35 and CYP2B37 structures are represented in mesh overlay. The 4-CPI molecules in the respective structures are shown as sticks.