Fig. 6.

Changes of the active site structure upon proteolytic activation of EcPOX. (A) Superposition of the active sites of full-length EcPOX (green) and EcPOX_Δ23 (yellow). Amino acids contributed from the neighboring subunit are labeled with an apostrophe. Note the position of F₄₆₅ in EcPOX_Δ23, which adopts a conformation identical to that of F₄₇₉ in LpPOX. (B) Illustration of the structural transition of the C-terminal linker region (residues 531–549) and an active center loop harboring F₄₆₅ upon proteolytic activation. The full-length enzyme is shown in green and EcPOX_Δ23 is shown in yellow. Residues Y₅₄₉ and F₄₆₅ are highlighted.