Lettau Elisabeth, Lorent Christian, Appel Jens, Boehm Marko, Cordero Paul R F, Lauterbach Lars
RWTH Aachen University, iAMB - Institute of Applied Microbiology, Worringerweg 1, 52074 Aachen, Germany; Technische Universität Berlin, Institute of Chemistry, Straße des 14. Juni 135, 10623 Berlin, Germany.
Technische Universität Berlin, Institute of Chemistry, Straße des 14. Juni 135, 10623 Berlin, Germany.
Biochim Biophys Acta Bioenerg. 2025 Jan 1;1866(1):149508. doi: 10.1016/j.bbabio.2024.149508. Epub 2024 Sep 6.
The NAD-reducing soluble [NiFe] hydrogenase (SH) is the key enzyme for production and consumption of molecular hydrogen (H) in Synechocystis sp. PCC6803. In this study, we focused on the reductase module of the SynSH and investigated the structural and functional aspects of its subunits, particularly the so far elusive role of HoxE. We demonstrated the importance of HoxE for enzyme functionality, suggesting a regulatory role in maintaining enzyme activity and electron supply. Spectroscopic analysis confirmed that HoxE and HoxF each contain one [2Fe2S] cluster with an almost identical electronic structure. Structure predictions, alongside experimental evidence for ferredoxin interactions, revealed a remarkable similarity between SynSH and bifurcating hydrogenases, suggesting a related functional mechanism. Our study unveiled the subunit arrangement and cofactor composition essential for biological electron transfer. These findings enhance our understanding of NAD-reducing [NiFe] hydrogenases in terms of their physiological function and structural requirements for biotechnologically relevant modifications.
NAD 还原型可溶性[NiFe]氢化酶（SH）是集胞藻 PCC6803 中分子氢（H₂）产生和消耗的关键酶。在本研究中，我们聚焦于 SynSH 的还原酶模块，研究了其亚基的结构和功能方面，特别是迄今为止尚不明确的 HoxE 的作用。我们证明了 HoxE 对酶功能的重要性，表明其在维持酶活性和电子供应方面具有调节作用。光谱分析证实，HoxE 和 HoxF 各自含有一个具有几乎相同电子结构的[2Fe2S]簇。结构预测以及铁氧化还原蛋白相互作用的实验证据表明，SynSH 与分叉氢化酶之间存在显著相似性，提示存在相关的功能机制。我们的研究揭示了生物电子传递所必需的亚基排列和辅因子组成。这些发现增进了我们对 NAD 还原型[NiFe]氢化酶在生理功能以及生物技术相关修饰的结构要求方面的理解。
