The Cyanide Ligands of [FeFe] Hydrogenase: Pulse EPR Studies of 13C and 15N-Labeled H-Cluster

详细信息    查看全文

• 作者：William K. Myers ; Troy A. Stich ; Daniel L. M. Suess ; Jon M. Kuchenreuther ; James R. Swartz ; R. David Britt
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：September 3, 2014
• 年：2014
• 卷：136
• 期：35
• 页码：12237-12240
• 全文大小：316K
• ISSN：1520-5126

文摘

The two cyanide ligands in the assembled cluster of [FeFe] hydrogenase originate from exogenous mallcaps">l-tyrosine. Using selectively labeled tyrosine substrates, the cyanides were isotopically labeled via a recently developed in vitro maturation procedure allowing advanced electron paramagnetic resonance techniques to probe the electronic structure of the catalytic core of the enzyme. The ratio of the isotropic ¹³C hyperfine interactions for the two CN^{鈥?/sup> ligands鈥攁 reporter of spin density on their respective coordinating iron ions鈥攃ollapses from 鈮?.8 for the H_ox form of hydrogenase to <2 for the CO-inhibited form. Additionally, when the maturation was carried out using [15N]-tyrosine, no features previously ascribed to the nitrogen of the bridging dithiolate ligand were observed suggesting that this bridge is not sourced from tyrosine.}