Characterization of an O2 adduct of an active cobalt-substituted extradiol-cleaving catechol dioxygenase.
Characterization of an O2 adduct of an active cobalt-substituted extradiol-cleaving catechol dioxygenase.
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DOI：
10.1021/ja2095365
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发表时间：
2012-01-18
影响因子：
15
通讯作者：
Que, Lawrence, Jr.
中科院分区：
文献类型：
--
作者：
Fielding, Andrew J.;Lipscomb, John D.;Que, Lawrence, Jr.
活性Co取代的加氧酶的O2加合物的第一个例子是在缺电子底物4-硝基儿茶酚（4NC）通过Co（II）-高原儿茶酸2，3-双加氧酶（Co-HPCD）的extradiol环裂解中观察到的。当O2结合到高自旋Co（II）（S = 3/2）酶-底物复合物时，观察到S = 1/2 EPR信号，其表现出典型的低自旋Co（III）-超氧化物复合物的59 Co超精细分裂（A = 24 G）。新中间体的形成和衰变都非常缓慢，与原生高自旋Fe（II）-HPCD（可能在O2结合时保持高自旋）对4NC进行周转的类似步骤相比。类似的，但有效稳定的，S = 1/2的中间体由非活性[H200N-Co-HPCD（4NC）]变体形成。所提出的意见阐明了基板，第二球His200残基，和自旋状态的金属中心在促进O2结合和激活中发挥的关键作用。
The first example for an O2 adduct of an active Co-substituted oxygenase is observed in the extradiol ring cleavage of the electron-poor substrate 4-nitrocatechol (4NC) by Co(II)-homoprotocatechuate 2,3-dioxygenase (Co-HPCD). Upon O2 binding to the high-spin Co(II) (S = 3/2) enzyme-substrate complex, an S = 1/2 EPR signal is observed exhibiting 59Co hyperfine splitting (A = 24 G) typical of a low-spin Co(III)-superoxide complex. Both formation and decay of the new intermediate are very slow in comparison to the analogous steps for turnover of 4NC by native high-spin Fe(II)-HPCD, which is likely to remain high-spin upon O2 binding. A similar, but effectively stable, S = 1/2 intermediate is formed by the inactive [H200N-Co-HPCD(4NC)] variant. The observations presented shed light on the key roles played by the substrate, the second-sphere His200 residue, and the spin state of the metal center in facilitating O2 binding and activation.
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影响因子：
3
作者：
Emerson, JP;Wagner, ML;Wackett, LP
通讯作者：
Wackett, LP
影响因子：
3
作者：
Fielding, Andrew J.;Kovaleva, Elena G.;Farquhar, Erik R.;Lipscomb, John D.;Que, Lawrence, Jr.
通讯作者：
Que, Lawrence, Jr.
影响因子：
2.9
作者：
Groce, SL;Miller-Rodeberg, MA;Lipscomb, JD
通讯作者：
Lipscomb, JD
影响因子：
15
作者：
HOFFMAN, BM;DIEMENTE, DL;BASOLO, F
通讯作者：
BASOLO, F
影响因子：
2.9
作者：
Mbughuni, Michael M.;Chakrabarti, Mrinmoy;Hayden, Joshua A.;Meier, Katlyn K.;Dalluge, Joseph J.;Hendrich, Michael P.;Muenck, Eckard;Lipscomb, John D.
通讯作者：
Lipscomb, John D.