Increase of Redox Potential during the Evolution of Enzymes Degrading Recalcitrant Lignin
Increase of Redox Potential during the Evolution of Enzymes Degrading Recalcitrant Lignin
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DOI：
10.1002/chem.201805679
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发表时间：
2019-02-21
影响因子：
4.3
通讯作者：
Martinez, Angel T.
中科院分区：
文献类型：
--
作者：
Ayuso-Fernandez, Ivan;De Lacey, Antonio L.;Martinez, Angel T.
为了研究木质素分解过氧化物酶如何获得它们今天所显示的独特的高氧化还原电位，它们的祖先被复活并表征。不幸的是，来自酶静息态（RS）的过氧化物活化的瞬时化合物I（Cl）和II（CII）是不稳定的。因此，从通过停流UV/维斯光谱分析的平衡浓度估计三种氧化还原对（CI/RS、CI/CII和CII/RS）的还原电位（E度）（首次在木质素分解过氧化物酶中）。有趣的是，从共同的过氧化物酶祖先到现存的木质素过氧化物酶（LiP），限速CII还原为RS的E度增加了70 mV，并且对于CI/RS和CI/CII观察到相同的增强，尽管具有更高的E度值。一个简单的相关性被发现之间的E度的值和近端的组氨酸H-1的NMR光谱中的化学位移的渐进位移，由于较高的顺磁效应的血红素Fe 3+。更有趣的是，E度和NMR数据也与进化时间相关，揭示了在过去的4亿年中，由于血红素口袋中的分子重排，祖先过氧化物酶在进化为LiP的过程中增加了它们的还原潜力。
To investigate how ligninolytic peroxidases acquired the uniquely high redox potential they show today, their ancestors were resurrected and characterized. Unfortunately, the transient Compounds I (CI) and II (CII) from peroxide activation of the enzyme resting state (RS) are unstable. Therefore, the reduction potentials (E degrees ') of the three redox couples (CI/RS, CI/CII and CII/RS) were estimated (for the first time in a ligninolytic peroxidase) from equilibrium concentrations analyzed by stopped-flow UV/Vis spectroscopy. Interestingly, the E degrees ' of rate-limiting CII reduction to RS increased 70 mV from the common peroxidase ancestor to extant lignin peroxidase (LiP), and the same boost was observed for CI/RS and CI/CII, albeit with higher E degrees ' values. A straightforward correlation was found between the E degrees ' value and the progressive displacement of the proximal histidine H epsilon 1 chemical shift in the NMR spectra, due to the higher paramagnetic effect of the heme Fe3+. More interestingly, the E degrees ' and NMR data also correlated with the evolutionary time, revealing that ancestral peroxidases increased their reduction potential in the evolution to LiP thanks to molecular rearrangements in their heme pocket during the last 400 million years.