| Arianna Bassan1, Tomasz Borowski2, Vladimir Pelmenschikov3, Christopher Schofield4, and Per Siegbahn3. (1) Department of Physics, Stockholm University, SE- 106 91 Stockholm, Sweden, (2) Department of Physics, Stockholm Center for Physics, Astronomy and, Stockholm University, S-106 91, Stockholm, Sweden, (3) Stockholm University, (4) Oxford University |
| The reaction catalyzed by the plant enzyme 1-aminocyclopropane-1-carboxylic acid oxidase (ACCO) has been investigated using hybrid density functional theory. ACCO plays a fundamental role in the biosynthesis of ethylene, which acts as a signaling molecule in many processes connected with plant development and defense (e.g., rooting, fruit ripening, germination). This enzyme carries out the two electron oxidation of the substrate ACC (1-aminocyclopropane-1-carboxylic acid) concomitantly with the four-electron reduction of dioxygen and oxidation of ascorbate. This complex reaction, which gives ethylene, CO$_2$ and cyanide occurs in the enzyme active site hosting a mononuclear non-heme iron center. A model including the metal complex and ACC coordinated in the first coordination sphere is used to study the details of O-O bond cleavage and cyclopropane ring opening. |
