Determination of the distance between the Mo(V) and Fe(III) heme centers of wild type human sulfite oxidase by pulsed EPR spectroscopy.
Determination of the distance between the Mo(V) and Fe(III) heme centers of wild type human sulfite oxidase by pulsed EPR spectroscopy.
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DOI：
10.1021/jp210578f
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发表时间：
2012-02-16
影响因子：
3.3
通讯作者：
Enemark, John H.
中科院分区：
文献类型：
--
作者：
Astashkin, Andrei V.;Rajapakshe, Asha;Cornelison, Matthew J.;Johnson-Winters, Kayunta;Enemark, John H.
脊椎动物亚硫酸盐氧化酶（SO）的钼中心和血红素中心之间的分子内电子转移（IET）被认为是该酶催化循环的关键步骤。然而，这些中心之间的X射线晶体学距离RMoFe = 32.3 μ m，对于在液体溶液中观察到的快速IET速率来说似乎太长了。Mo和血红素域通过柔性系链连接，并且已经提出动态域间运动使两个金属中心更靠近在一起，从而促进快速IET。到目前为止，还没有直接的距离测量SO的解决方案，将支持或反驳这个模型。在这项工作中，脉冲电子-电子双共振（ELDOR）和弛豫诱导的偶极调制增强（RIDME）技术被用来获得有关RMoFe在Mo（V）Fe（III）状态的野生型重组人SO在冷冻玻璃溶液中的信息。令人惊讶的是，所获得的数据表明RMoFe = 32 π的固定结构，类似于通过X射线晶体学测定的鸡SO，尽管RMoFe半径矢量相对于血红素中心的取向被发现有些不同。这些研究结果的柔性系绳模型的影响进行了讨论。
Intramolecular electron transfer (IET) between the molybdenum and heme centers of vertebrate sulfite oxidase (SO) is proposed to be a key step in the catalytic cycle of the enzyme. However, the X-ray crystallographic distance between these centers, RMoFe = 32.3 Å, appears to be too long for the rapid IET rates observed in liquid solution. The Mo and heme domains are linked by a flexible tether, and it has been proposed that dynamic interdomain motion brings the two metal centers closer together and thereby facilitates rapid IET. To date there have been no direct distance measurements for SO in solution that would support or contradict this model. In this work, pulsed electron-electron double resonance (ELDOR) and relaxation induced dipolar modulation enhancement (RIDME) techniques were used to obtain information about RMoFe in the Mo(V)Fe(III) state of wild type recombinant human SO in frozen glassy solution. Surprisingly, the data obtained suggest a fixed structure with RMoFe = 32 Å, similar to that determined by X-ray crystallography for chicken SO, although the orientation of the RMoFe radius-vector with respect to the heme center was found to be somewhat different. The implications of these findings for the flexible tether model are discussed.
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影响因子：
2.2
作者：
KURSHEV, VV;RAITSIMRING, AM;TSVETKOV, YD
通讯作者：
TSVETKOV, YD
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影响因子：
56.9
作者：
BERATAN, DN;ONUCHIC, JN;GRAY, HB
通讯作者：
GRAY, HB
影响因子：
15
作者：
Elsässer, C;Brecht, M;Bittl, R
通讯作者：
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影响因子：
3.3
作者：
Gordon-Grossman, Michal;Kaminker, Ilia;Goldfarb, Daniella
通讯作者：
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DOI：
10.1002/cmr.b.20064
发表时间：
2006-08-01
影响因子：
0.9
作者：
Astashkin, A. V.;Enemark, J. H.;Raitsimring, A.
通讯作者：
Raitsimring, A.