The Catalytic Reaction Mechanism of the β-Galactocerebrosidase Enzyme Deficient in Krabbe Disease
The Catalytic Reaction Mechanism of the β-Galactocerebrosidase Enzyme Deficient in Krabbe Disease
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DOI：
10.1021/acscatal.0c02609
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发表时间：
2020-10-16
期刊：
影响因子：
12.9
通讯作者：
Rovira, Carme
中科院分区：
文献类型：
--
作者：
Nin-Hill, Alba;Rovira, Carme
克拉伯病是一种与β-半乳糖苷酶（GALC）功能障碍相关的神经退行性疾病，GALC是一种催化鞘糖脂中β-半乳糖苷键裂解的糖苷酶。在这里，我们揭示了GALC的催化分子机制，用量子力学/分子力学方法。我们的研究结果澄清了在晶体结构中观察到的底物的不寻常的椅子构象，并表明催化可以通过两种不同的构象途径（S-1（3）-> [H-4（3）]double dagger -> C-4（1）和C-4（1）->[H-4（3）]double dagger -> C-4（1））进行，由于离去基团的灵活性，具有相似的自由能垒。这一机制的见解将有助于设计的Krabbe诊断探针和GALC构象伴侣。
Krabbe disease is a neurodegenerative disorder related to misfunction of beta-galactocerebrosidase (GALC), a glycosidase that catalyzes the cleavage of beta-galactosidic bonds in glycosphingolipids. Here we uncover the catalytic molecular mechanism of GALC using quantum mechanics/molecular mechanics methods. Our results clarify the unusual chair conformation of the substrate observed in the crystal structure and show that catalysis can take place via two distinct conformational pathways (S-1(3) -> [H-4(3)]double dagger -> C-4(1) and C-4(1) ->[H-4(3)]double dagger -> C-4(1)) with similar free energy barriers because of leaving group flexibility. This mechanistic insight will aid in the design of Krabbe diagnosis probes and GALC conformational chaperones.