7C8N

Crystal structure of IscU H106A variant

7C8N の概要

• エントリーDOI: 10.2210/pdb7c8n/pdb
• 分子名称: Nitrogen-fixing NifU domain protein, FE2/S2 (INORGANIC) CLUSTER (3 entities in total)
• 機能のキーワード: iron-sulfur cluster biogenesis, biosynthetic protein
• 由来する生物種: Methanothrix thermoacetophila
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 15373.21

構造登録者

Kunichika, K.,Takahashi, Y.,Fujishiro, T. (登録日: 2020-06-03, 公開日: 2021-05-26, 最終更新日: 2023-11-29)

主引用文献

Kunichika, K.,Nakamura, R.,Fujishiro, T.,Takahashi, Y.
The Structure of the Dimeric State of IscU Harboring Two Adjacent [2Fe-2S] Clusters Provides Mechanistic Insights into Cluster Conversion to [4Fe-4S].
Biochemistry, 60:1569-1572, 2021

PubMed Abstract: IscU serves as a scaffold for the assembly of a [2Fe-2S] cluster prior to its delivery to recipient protein. It has also been proposed that on one dimer of bacterial IscU, two [2Fe-2S] clusters can be converted into a single [4Fe-4S] cluster. However, lack of structural information about the dimeric state of IscU has hindered our understanding of the underlying mechanisms. In this study, we determine the X-ray crystal structure of IscU from the thermophilic archaeon and demonstrate a dimer structure of IscU in which two [2Fe-2S] clusters are facing each other in close proximity at the dimer interface. Our structure also reveals for the first time that Asp40 serves as a fourth ligand to the [2Fe-2S] cluster with three Cys ligands in each monomer, consistent with previous spectroscopic data. We confirm by EPR spectroscopic analysis that in solution two adjacent [2Fe-2S] clusters in the wild-type dimer are converted to a [4Fe-4S] cluster via reductive coupling. Furthermore, we find that the H106A substitution abolishes the reductive conversion to the [4Fe-4S] cluster without structural alteration, suggesting that His106 is functionally involved in this process. Overall, these findings provide a structural explanation for the assembly and conversion of Fe-S clusters on IscU and highlight a dynamic process that advances via association and dissociation of the IscU dimer.

PubMed: 33938220
DOI: 10.1021/acs.biochem.1c00112

実験手法

X-RAY DIFFRACTION (1.5 Å)