Shoji Mitsuo, Murakawa Takeshi, Boero Mauro, Shigeta Yasuteru, Hayashi Hideyuki, Okajima Toshihide
Center for Computational Sciences, University of Tsukuba 1-1-1 Tennodai Tsukuba Ibaraki 305-8577 Japan
JST-PRESTO 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan.
RSC Adv. 2020 Oct 21;10(63):38631-38639. doi: 10.1039/d0ra06365g. eCollection 2020 Oct 15.
The oxidative deamination of biogenic amines, crucial in the metabolism of a wealth of living organisms, is catalyzed by copper amine oxidases (CAOs). In this work, on the ground of accurate molecular modeling, we provide a clear insight into the unique protonation states of the key catalytic aspartate residue Asp298 and the prosthetic group of topaquinone (TPQ) in the CAO of (AGAO). This provides both extensions and complementary information to the crystal structure determined by our recent neutron diffraction (ND) experiment. The hybrid quantum mechanics/molecular mechanics (QM/MM) simulations suggest that the ND structure closely resembles a state in which Asp298 is protonated and the TPQ takes an enolate form. The TPQ keto form can coexist in the fully protonated state. The energetic and structural analyses indicate that the active site structure of the AGAO crystal is not a single state but rather a mixture of the different protonation and conformational states identified in this work.
生物胺的氧化脱氨作用在众多生物体的新陈代谢中至关重要，它由铜胺氧化酶（CAOs）催化。在这项工作中，基于精确的分子建模，我们深入了解了嗜热栖热放线菌铜胺氧化酶（AGAO）中关键催化天冬氨酸残基Asp298和topaquinone（TPQ）辅基的独特质子化状态。这为我们最近通过中子衍射（ND）实验确定的晶体结构提供了扩展和补充信息。量子力学/分子力学（QM/MM）混合模拟表明，ND结构与Asp298质子化且TPQ呈烯醇式的状态非常相似。TPQ酮式可以以完全质子化状态共存。能量和结构分析表明，AGAO晶体的活性位点结构不是单一状态，而是这项工作中确定的不同质子化和构象状态的混合物。
