Exposing catalytic versatility of GTPases: taking reaction detours in mutants of hGBP1 enzyme without additional energetic cost.
Exposing catalytic versatility of GTPases: taking reaction detours in mutants of hGBP1 enzyme without additional energetic cost.
复制标题
揭示 GTP 酶的催化多功能性：在 hGBP1 酶突变体中采取反应弯路，无需额外的能量成本
DOI：
10.1039/c8cp06343e
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
D. Marx
中科院分区：
文献类型：
--
作者：
R. Tripathi;J. Noetzel;D. Marx
酶的催化能力通常归因于少数催化活性残基，如结合生化、热力学和结构分析的定点突变研究所揭示的那样。令人惊讶的是，GTP酶中这些关键残基的突变可以将GTP甚至水解成GMP，即hGBP1，与野生型相比，仅导致催化速率的微小变化。我们的大规模从头计算量子力学/分子力学(QM/MM)元动力学模拟表明，惰性氨基酸丙氨酸、S73A和E99A取代催化活性残基，打开了大量分子上不同的反应路径，具有非常相似的能垒和速率。这些迄今未知的反应通道是通过使用“浮动”水分子从机械上涉及远距离残基建立的，这些分子通过氢键桥将它们连接到亲核水分子，从而允许通过格洛特斯机制进行有效的长距离质子转移。鉴于所公开的迂回机制的一般性，这些机制提供了催化多功能性的分子基础，从而提供了hGBP1的突变稳健性，预计同样的概念在广义上也适用于GTP酶。
The catalytic power of enzymes is usually ascribed to a few catalytically competent residues as revealed by site-directed mutagenesis studies in conjunction with biochemical, thermodynamic and structural analyses. Surprisingly, the mutations of such pivotal residues in a GTPase that can hydrolyse GTP even to GMP, namely hGBP1, have been reported to result only in marginal changes of the catalytic rate compared to the wild type. Our large-scale ab initio quantum-mechanical/molecular-mechanical (QM/MM) metadynamics simulations disclose that the replacement of catalytically competent residues by the inert amino acid alanine, S73A and E99A, opens a plethora of molecularly different reaction pathways featuring very similar energy barriers and thus rates. These hitherto unknown reaction channels are established by mechanistically involving far-distant residues using “floating” water molecules, which connect them via hydrogen-bonding bridges to the nucleophilic water molecule, thus allowing for efficient long-distance proton transfer via the Grotthuss mechanism. Given the generic nature of the disclosed detour mechanisms that provide the molecular underpinning of catalytic versatility and thus mutational robustness of hGBP1, it is expected that the same concept is operational for GTPases in a broad sense.
登录
查看更多内容
影响因子：
17.3
作者：
Wagner,CR;Benkovic,SJ
通讯作者：
Benkovic,SJ
影响因子：
14.9
作者：
Prado S;Villarroya M;Medina M;Armengod ME
通讯作者：
Armengod ME
修补酶：我们学到了什么？
影响因子：
56.9
作者：
J. Knowles
通讯作者：
J. Knowles
影响因子：
4.8
作者：
Kunzelmann, Simone;Praefcke, Gerrit J. K.;Herrmann, Christian
通讯作者：
Herrmann, Christian
影响因子：
2.9
作者：
Guofeng Zhang;M. Morais;Jianying Dai;Wenhai Zhang;D. Dunaway-Mariano;Karen N Allen-
通讯作者：
Guofeng Zhang;M. Morais;Jianying Dai;Wenhai Zhang;D. Dunaway-Mariano;Karen N Allen-