Four second-sphere residues of Thermus thermophilus SG0.5JP17-16 laccase tune the catalysis by hydrogen-bonding networks
Four second-sphere residues of Thermus thermophilus SG0.5JP17-16 laccase tune the catalysis by hydrogen-bonding networks
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嗜热栖热菌 SG0.5JP17-16 漆酶的四个第二球残基通过氢键网络调节催化作用
DOI：
10.1007/s00253-018-8875-y
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发表时间：
2018-03
影响因子：
5
通讯作者：
Lin Ying
中科院分区：
文献类型：
--
作者：
Liu Huiping;Zhu Yanyun;Yang Xiaorong;Lin Ying
多铜氧化酶催化四个底物分子的1-电子氧化，并伴随着分子氧的4-电子还原为水。底物在酶的1型铜（T1 Cu）位点失去电子，而分子氧在三核铜中心被还原为水。一个高度保守的Glu残基，它位于双氧进入通道，穿梭质子以打破双氧的O-O键。在水离开通道，天冬氨酸残基被发现是重要的质子化机制。本研究以嗜热栖热菌SG0.5JP17-16（lacTT）漆酶为研究对象，探讨了第二球残基E356、E456、D106和D423对漆酶活性的影响。动力学数据表明，该酶的催化活性改变了四个第二球残基上的定点诱变。通过同源建模产生lacTT的结构模型。结构和光谱数据表明，E356残基位于底物结合位点，负责通过氢键网络结合底物和T1 Cu位点的几何形状;位于双氧进入通道的E456残基，在稳定所有活性铜中心的结构和将质子穿梭到三核铜簇（TNC）中起着关键作用D106和D423残基位于离水通道，它们对TNC的基本几何结构和水分子的释放都很重要。总之，这项研究有助于进一步了解的基本机制，涉及底物的氧化，电子转移，并在lacTT的分子氧的还原。
The multicopper oxidases catalyze 1-electron oxidation of four substrate molecules and concomitantly 4-electron reduction of dioxygen to water. The substrate loses the electrons at the type 1 copper (T1 Cu) site of the enzyme, while the dioxygen is reduced to water at the trinuclear copper center. A highly conserved Glu residue, which is at the dioxygen-entering channel, shuttles the proton to break the O-O bond of dioxygen. At the water-leaving channel, an Asp residue was found to be important in the protonation mechanism. In this study, laccase from Thermus thermophilus SG0.5JP17-16 (lacTT) was investigated to address how four second-sphere residues E356, E456, D106, and D423 affect the activity of the enzyme. Kinetic data indicate that catalytic activities of the enzyme are altered by site-directed mutagenesis on four second-sphere residues. The structural model of lacTT was generated by homology modeling. Structural and spectral data indicate that the E356 residue is situated at the substrate-binding site, responsible for the binding of the substrate and the geometry of the T1 Cu site by hydrogen-bonding networks; the E456 residue, located at the dioxygen-entering channel, plays a critical role in stabilizing the structure of all active copper centers and shuttling the proton to the trinuclear copper cluster (TNC) for the reductive reaction of dioxygen; the D106 and D423 residues are at the water-leaving channel, and they are important for the essential geometry of the TNC and the release of the water molecules. Altogether, this study contributes to the further understanding of the basic mechanism involving the oxidation of the substrate, electron transfer, and the reduction of dioxygen in lacTT.
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影响因子：
5.6
作者：
Kataoka, Kunishige;Komori, Hirofumi;Sakurai, Takeshi
通讯作者：
Sakurai, Takeshi
影响因子：
2.9
作者：
L. Quintanar;C. Stoj;Tzu-Pin Wang;D. Kosman;E. Solomon
通讯作者：
L. Quintanar;C. Stoj;Tzu-Pin Wang;D. Kosman;E. Solomon
影响因子：
3.5
作者：
Yusaku Ueki;Megumi Inoue;S. Kurose;K. Kataoka;T. Sakurai
通讯作者：
Yusaku Ueki;Megumi Inoue;S. Kurose;K. Kataoka;T. Sakurai
影响因子：
0.2
作者：
Jean Guillon;Maria de Fatima Pereira-Rosenfeld;Noël Pinaud;Thierry Besson;Valérie Thiéry;Laurent Picot-Laurent
通讯作者：
Jean Guillon;Maria de Fatima Pereira-Rosenfeld;Noël Pinaud;Thierry Besson;Valérie Thiéry;Laurent Picot-Laurent
DOI：
10.1007/s00775-013-1080-7
发表时间：
2014-01
期刊：
JBIC Journal of Biological Inorganic Chemistry
影响因子：
--
作者：
S. Wherland;O. Farver;I. Pecht
通讯作者：
S. Wherland;O. Farver;I. Pecht