Structural chemistry of O2-tolerant [NiFe]-hydrogenases

2015 Fiscal Year Final Research Report

• Project/Area Number: 25291038
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Biophysics
• Research Institution: University of Hyogo
• Principal Investigator: Higuchi Yoshiki 兵庫県立大学, 生命理学研究科, 教授 (90183574)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: X線結晶解析 / 酸素耐性酵素 / Ni酵素 / ヒドロゲナーゼ / 燃料電池 / 中性子結晶解析 / 反応機構 / プロトンチャネル

Outline of Final Research Achievements

In this study, x-ray structure analysis of newly found O2-tolerant [NiFe]-hydrogenase and neutron structure analysis of standard enzyme have been carried out.
1. The x-ray structures of the newly found O2-tolerant [NiFe]-hydrogenase from Citrobacter sp. S-77 in the air-oxidized, K3Fe(CN)6-oxidized and H2-reduced forms have been successfully solved at the resolutions better than 2.0 A. The one of the iron-sulfur clusters (the proximal to the Ni-Fe active site) is not a [4Fe3S]-type, which was found in the usual O2-tolerant enzymes, but a [4Fe4S]-type typical as those in the standard enzymes. This [4Fe4S]-type cluster changed its structure when the enzyme is oxidized by K3Fe(CN)6, but the mechanism of the structural changed are different from those clusters in O2-tolerant hydrogenase.
2. Neutron diffraction data up to 2.0 A resolution have been successfully obtained from a large crystal (>1.5 mm3) grown in D2O.

Free Research Field

構造生物学