Furukawa Yoshiaki, Megata Masamichi, Shintani Atsuko, Sue Kaori, Morohoshi Tomohiro, Akutsu Masato, Muraki Norifumi
Department of Chemistry, Keio University, Yokohama, Kanagawa, Japan.
Department of Chemistry, Keio University, Yokohama, Kanagawa, Japan.
J Biol Chem. 2025 Jul 18;301(8):110499. doi: 10.1016/j.jbc.2025.110499.
Cu/Zn-superoxide dismutase (Cu/Zn-SOD) is an antioxidant enzyme widely present across species; however, the structural diversity and physiological roles of Cu/Zn-SOD are yet to be fully uncovered. Here, we show a unique type of Cu/Zn-SOD from Deinococcus radiodurans (DrSOD) with an additional β-propeller domain. Our structural analysis of DrSOD revealed a typical bacterial Cu/Zn-SOD domain, binding both a copper and zinc ion, alongside a six-bladed β-propeller domain coordinating a calcium ion. DrSOD was indeed expressed in D. radiodurans, but its deletion did not lead to any noticeable changes in resistance to DNA-damaging stresses, a characteristic trait of D. radiodurans. Despite this, the Cu/Zn-SOD domain retained superoxide dismutase activity, and the β-propeller domain was found to exhibit a lactonase activity specifically for hydrolyzing 2-coumaranone. Taken together, while the precise physiological role of DrSOD needs to be further investigated, our findings here reveal a unique multi-functional enzyme architecture, expanding the known structural diversity of Cu/Zn-SODs.
铜锌超氧化物歧化酶（Cu/Zn-SOD）是一种广泛存在于各物种中的抗氧化酶；然而，Cu/Zn-SOD的结构多样性和生理作用尚未完全揭示。在此，我们展示了一种来自耐辐射球菌（DrSOD）的独特类型的Cu/Zn-SOD，它带有一个额外的β-螺旋桨结构域。我们对DrSOD的结构分析揭示了一个典型的细菌Cu/Zn-SOD结构域，它结合了一个铜离子和一个锌离子，同时还有一个六叶β-螺旋桨结构域配位一个钙离子。DrSOD确实在耐辐射球菌中表达，但其缺失并未导致对DNA损伤应激的抗性出现任何明显变化，而抗性是耐辐射球菌的一个特征特性。尽管如此，Cu/Zn-SOD结构域保留了超氧化物歧化酶活性，并且发现β-螺旋桨结构域表现出一种专门用于水解2-香豆酮的内酯酶活性。综上所述，虽然DrSOD的确切生理作用需要进一步研究，但我们在此的发现揭示了一种独特的多功能酶结构，扩展了已知的Cu/Zn-SOD的结构多样性。
