Kühnel Karin, Derat Etienne, Terner James, Shaik Sason, Schlichting Ilme
Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
Proc Natl Acad Sci U S A. 2007 Jan 2;104(1):99-104. doi: 10.1073/pnas.0606285103. Epub 2006 Dec 26.
We have determined the crystal structure of the chloroperoxidase (CPO) hydroperoxo reaction intermediate (CPO compound 0) at 1.75-A resolution. The intermediate was generated through controlled photoreduction of the CPO oxygen complex during x-ray data collection, which was monitored by recording of the crystal absorption spectra. Initially, the peroxo-anion species was formed and then protonated to yield compound 0. Quantum chemical calculations indicate that the peroxo-anion species is not stable and collapses instantaneously to compound 0. Compound 0 is present in the ferric low-spin doublet ground state and is characterized by a long O O bond length of 1.5 A and a Fe O bond distance of 1.8 A, which is also observed in the crystal structure.
我们已确定氯过氧化物酶(CPO)氢过氧反应中间体(CPO化合物0)在1.75埃分辨率下的晶体结构。该中间体是在X射线数据收集过程中通过对CPO氧复合物进行可控光还原生成的,这一过程通过记录晶体吸收光谱进行监测。最初,过氧阴离子物种形成,然后质子化生成化合物0。量子化学计算表明,过氧阴离子物种不稳定,会瞬间分解为化合物0。化合物0以三价铁低自旋双重态基态存在,其特征是O—O键长为1.5埃,Fe—O键距为1.8埃,这在晶体结构中也有观察到。