Investigation of catalytic mechanism of heme oxygenase and protein-protein interaction among its related enzymes

2014 Fiscal Year Final Research Report

• Project/Area Number: 24510301
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Living organism molecular science
• Research Institution: Kyushu Institute of Technology
• Principal Investigator: SAKAMOTO Hiroshi 九州工業大学, 大学院情報工学研究院, 教授 (70309748)
• Co-Investigator(Kenkyū-buntansha): YASUNAGA Takuo 九州工業大学, 大学院情報工学研究院, 教授 (60251394) ; KOMATSU Hideyuki 九州工業大学, 大学院情報工学研究院, 助教 (90253567)
• Co-Investigator(Renkei-kenkyūsha): NOGUCHI Masato 久留米大学, 医学部, 教授 (10124611)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: ヘム / ヘムオキシゲナーゼ / シトクロムP450還元酵素 / 蛋白質間相互作用

Outline of Final Research Achievements

Heme oxygenase (HO) catalyzes the O2-dependent degradation of heme using reducing equivalents from NADPH-cytochrome P450 reductase (CPR) and produces biliverdin, CO, and iron. Without reducing reagents, HO does not exhibit heme degradation activity but retains high substrate affinity to form a stable complex with heme. The heme bindings of wild-type HO-1 and its mutants were analyzed using isothermal titration calorimetry. Heme regulatory motifs at the C terminus of HO-2 were synthesized and their heme binding properties were investigated.
For electron transfer as well as product release, HO and CPR should repeat a cycle of association and dissociation, thus there might be some kind of regulation of protein-protein interaction between them. Using surface plasmon resonance we identified surface amino acids of HO-2 essential for binding to and/or electron transfer CPR. Furthermore, equilibrium associative properties between HO-1 and CPR were determined by analytical ultracentrifugation.

Free Research Field

生化学