An N⋯H⋯N low-barrier hydrogen bond preorganizes the catalytic site of aspartate aminotransferase to facilitate the second half-reaction.
An N⋯H⋯N low-barrier hydrogen bond preorganizes the catalytic site of aspartate aminotransferase to facilitate the second half-reaction.
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DOI：
10.1039/d2sc02285k
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发表时间：
2022-08-31
期刊：
影响因子：
8.4
通讯作者：
中科院分区：
文献类型：
--
作者：
吡哆醛5 ' -磷酸（PLP）依赖性酶因其微调PLP辅助因子电子以促进广泛化学反应的能力而被广泛研究。中子晶体学提供了一种直接的方法来研究PLP的电子状态和酶活性位点的静电，负责反应的特异性，通过实现氢原子位置的直接可视化。本文报道了天冬氨酸转氨酶（AAT）与pyridoxamine 5 ' -phosphate （PMP）的室温x射线/中子联合结构，PMP是由该酶催化的前半反应的辅因子产物。在PMP NSB和催化Lys258 Nζ氨基之间，在明显的低势垒氢键（LBHB）中观察到一个相等共享的氘。密度泛函理论计算提供了LBHB相互作用的进一步证据。PMP和Lys258的结构排列和并置，在LBHB的促进下，表明进入的酮酸底物的活性位点预先组织启动了第二个半反应。pyridoxar 5 ' -phosphate-dependent enzyme with pyridoxamine 5 ' -phosphate (PMP))的neutron structure揭示了PMP的氨基与催化剂Lys258之间存在一个低势垒氢键，预先组织了催化活性位点
Pyridoxal 5′-phosphate (PLP)-dependent enzymes have been extensively studied for their ability to fine-tune PLP cofactor electronics to promote a wide array of chemistries. Neutron crystallography offers a straightforward approach to studying the electronic states of PLP and the electrostatics of enzyme active sites, responsible for the reaction specificities, by enabling direct visualization of hydrogen atom positions. Here we report a room-temperature joint X-ray/neutron structure of aspartate aminotransferase (AAT) with pyridoxamine 5′-phosphate (PMP), the cofactor product of the first half reaction catalyzed by the enzyme. Between PMP NSB and catalytic Lys258 Nζ amino groups an equally shared deuterium is observed in an apparent low-barrier hydrogen bond (LBHB). Density functional theory calculations were performed to provide further evidence of this LBHB interaction. The structural arrangement and the juxtaposition of PMP and Lys258, facilitated by the LBHB, suggests active site preorganization for the incoming ketoacid substrate that initiates the second half-reaction. The neutron structure of pyridoxal 5′-phosphate-dependent enzyme aspartate aminotransferase with pyridoxamine 5′-phosphate (PMP) reveals a low-barrier hydrogen bond between the amino groups of PMP and catalytic Lys258, preorganizing the active site for catalysis
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DOI：
10.1107/s0907444909011548
发表时间：
2009-06
影响因子：
2.2
作者：
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发表时间：
2004-12-01
影响因子：
2.2
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DOI：
10.1107/s0907444998003254
发表时间：
1998-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
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Brunger, AT;Adams, PD;Warren, GL
通讯作者：
Warren, GL
影响因子：
15
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Benedict, H;Limbach, HH;Janoschek, R
通讯作者：
Janoschek, R