Ultrafast infrared spectroscopy reveals water-mediated coherent dynamics in an enzyme active site.
Ultrafast infrared spectroscopy reveals water-mediated coherent dynamics in an enzyme active site.
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DOI：
10.1039/c4sc02752c
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发表时间：
2015-01-01
期刊：
影响因子：
8.4
通讯作者：
Hunt NT
中科院分区：
文献类型：
--
作者：
Adamczyk K;Simpson N;Greetham GM;Gumiero A;Walsh MA;Towrie M;Parker AW;Hunt NT
超快红外光谱提供了对过氧化氢酶和过氧化物酶活性位点中水的动态性质的见解。了解快速动力学对蛋白质和酶活性位点内发生的化学过程的影响是一个关键的挑战，继续吸引显着的兴趣，虽然在溶液相的直接实验见解仍然稀少。在我们的知识中存在类似的差距，在理解水所发挥的作用，无论是作为溶剂或作为活性位点的结构/动态组件。为了进一步研究水的潜在生物作用，我们采用了超快多维红外光谱实验，直接探测NO的结构和振动动力学结合的过氧化氢酶从谷氨酸棒杆菌在H2O和D2 O的铁血红素。尽管过氧化氢酶有什么被认为是一个溶剂不可接近的活性位点，同位素依赖的光谱扩散和振动寿命参数的NO伸缩振动观察，表明水分子直接与血红素配体相互作用。此外，IR泵浦-探测数据的特征振荡起源于制备的低频振动模式的相干叠加在过氧化氢酶的活性位点，耦合到血红素配体的伸缩振动。与密切相关的过氧化物酶家族的范例的比较显示，它们也表现出溶剂依赖性活性位点动力学，支持血红素配体和水分子之间在过氧化氢酶和过氧化物酶两者的活性位点中的相互作用的存在，所述相互作用可能与导致铁基中间体化合物I的形成的质子转移事件有关。此外，一个强大的，水介导的，氢键结构的建议发生在过氧化氢酶，不复制在过氧化物酶;观察，可能揭示了这两种酶的不同功能的起源。
Ultrafast infrared spectroscopy provides insights into the dynamic nature of water in the active sites of catalase and peroxidase enzymes. Understanding the impact of fast dynamics upon the chemical processes occurring within the active sites of proteins and enzymes is a key challenge that continues to attract significant interest, though direct experimental insight in the solution phase remains sparse. Similar gaps in our knowledge exist in understanding the role played by water, either as a solvent or as a structural/dynamic component of the active site. In order to investigate further the potential biological roles of water, we have employed ultrafast multidimensional infrared spectroscopy experiments that directly probe the structural and vibrational dynamics of NO bound to the ferric haem of the catalase enzyme from Corynebacterium glutamicum in both H2O and D2O. Despite catalases having what is believed to be a solvent-inaccessible active site, an isotopic dependence of the spectral diffusion and vibrational lifetime parameters of the NO stretching vibration are observed, indicating that water molecules interact directly with the haem ligand. Furthermore, IR pump–probe data feature oscillations originating from the preparation of a coherent superposition of low-frequency vibrational modes in the active site of catalase that are coupled to the haem ligand stretching vibration. Comparisons with an exemplar of the closely-related peroxidase enzyme family shows that they too exhibit solvent-dependent active-site dynamics, supporting the presence of interactions between the haem ligand and water molecules in the active sites of both catalases and peroxidases that may be linked to proton transfer events leading to the formation of the ferryl intermediate Compound I. In addition, a strong, water-mediated, hydrogen bonding structure is suggested to occur in catalase that is not replicated in peroxidase; an observation that may shed light on the origins of the different functions of the two enzymes.
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影响因子：
3.3
作者：
Antoniou, Dimitri;Schwartz, Steven D.
通讯作者：
Schwartz, Steven D.
影响因子：
2.9
作者：
Brookes, Jennifer F.;Slenkamp, Karla M.;Khalil, Munira
通讯作者：
Khalil, Munira
DOI：
10.1038/nsb1297-1032
发表时间：
1997-12-01
期刊：
NATURE STRUCTURAL BIOLOGY
影响因子：
--
作者：
Gajhede, M;Schuller, DJ;Poulos, TL
通讯作者：
Poulos, TL
影响因子：
15
作者：
Bagchi, Sayan;Nebgen, Benjamin T.;Fayer, M. D.
通讯作者：
Fayer, M. D.
影响因子：
15
作者：
Derat, Etienne;Shaik, Sason
通讯作者：
Shaik, Sason