Mössbauer studies of the ferryl, ferrous and ferric states of dehaloperoxidase from A. ornata
Mössbauer studies of the ferryl, ferrous and ferric states of dehaloperoxidase from A. ornata
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穆斯堡尔对 A. ornata 脱卤过氧化物酶的铁态、亚铁态和三价铁态的研究
DOI：
10.1016/j.jinorgbio.2022.111867
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发表时间：
2022
影响因子：
3.9
通讯作者：
Ghiladi, Reza A.
中科院分区：
文献类型：
--
作者：
Popescu, C.V.;Dinh, Thanhminh;Chen, Hongli;Miller, Danielle;Washburn, Anastasia;McGuire, Ashlyn;Dumarieh, Rania;D'Antonio, Jennifer;Ghiladi, Reza A.
去盐过氧化物酶（DHP）是一种来自海洋蠕虫的多功能催化珠蛋白。其生理功能包括氧运输和氧化存在于其栖息地的有毒底物。在Fe（III）状态下，DHPA具有0.42 mm/s的同分异构体位移，这是高自旋血红素蛋白的特征。pH的变化对DHP在Fe（III）态的电子结构有微妙的影响，在高场光谱中可以检测到，这表明在5和18 cm−1之间具有不同零场分裂的物质的pH依赖混合物。由Fe（III）酶与h2o2直接反应得到的短寿命中间体的异构体位移为0.10 mm/s，表明Fe(IV)-氧态和s = 1电子基态已被变场研究证实。DHP的o2结合态具有0.28 mm/s的同分异构体位移和抗磁性血红素复合物的高场光谱特征，类似于其他血红蛋白。总的来说，研究的四种状态DHP的同分异构体移位和四极分裂预期与过氧化物酶和肌红蛋白相似。DHP与其他血红素蛋白和酶之间的电子结构差异在铁态的高场Mössbauer光谱中被观察到，它显示出ph依赖的零场分裂，表明血红素位点在铁离子处的配体场强可通过ph调节。这种可调性与铁的可变给电子特性有关，可以执行多种功能。
Dehaloperoxidase (DHP) is a multi-functional catalytic globin from the marine wormA. ornata, whose physiological functions include oxygen transport and oxidation of toxic substrates present in its habitat. In the Fe(III) state, DHPA has an isomer shift of 0.42 mm/s, characteristic for high-spin heme proteins. Changes in pH have subtle effects on the electronic structure of DHP in the Fe(III) state detectable in the high-field spectra, which show a pH-dependent mixture of species with different zero-field splittings between 5 and 18 cm−1. The short-lived intermediate obtained by direct reaction of the Fe(III) enzyme with H2O2has an isomer shift of 0.10 mm/s, indicative of an Fe(IV)-oxo state and of an S = 1 electronic ground state confirmed by variable field studies. The O2-bound state of DHP has an isomer shift of 0.28 mm/s and a high-field spectrum characteristic for diamagnetic heme complexes, similarly to other haemoglobins.Overall, the isomer shift and quadrupole splitting of DHP in the four states studied are expectedly similar to both peroxidases and to myoglobin. The differences in electronic structure between DHP and other heme proteins and enzyme are observed in the high-field Mössbauer spectra of the ferric state, which show pH-dependent zero-field splittings suggesting a heme site in which the ligand field strength at the iron ion is tuned by pH. This tunability is correlated with variable electron-donating properties of the iron, which can perform multiple functions.