8E3V

Cobalt-reconstituted nitrogenase MoFeP mutant S188A from Azotobacter vinelandii after IDS oxidation

8E3V の概要

• エントリーDOI: 10.2210/pdb8e3v/pdb
• 分子名称: Nitrogenase molybdenum-iron protein alpha chain, Nitrogenase molybdenum-iron protein beta chain, 3-HYDROXY-3-CARBOXY-ADIPIC ACID, ... (7 entities in total)
• 機能のキーワード: mofep, mofe-protein, oxidoreductase
• 由来する生物種: Azotobacter vinelandii DJ; 詳細
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 233207.17

構造登録者

Rutledge, H.L.,Tezcan, F.A. (登録日: 2022-08-17, 公開日: 2022-12-14, 最終更新日: 2023-10-25)

主引用文献

Rutledge, H.L.,Field, M.J.,Rittle, J.,Green, M.T.,Tezcan, F.A.
Role of Serine Coordination in the Structural and Functional Protection of the Nitrogenase P-Cluster.
J.Am.Chem.Soc., 144:22101-22112, 2022

PubMed Abstract: Nitrogenase catalyzes the multielectron reduction of dinitrogen to ammonia. Electron transfer in the catalytic protein (MoFeP) proceeds through a unique [8Fe-7S] cluster (P-cluster) to the active site (FeMoco). In the reduced, all-ferrous (P) state, the P-cluster is coordinated by six cysteine residues. Upon two-electron oxidation to the P state, the P-cluster undergoes conformational changes in which a highly conserved oxygen-based residue (a Ser or a Tyr) and a backbone amide additionally ligate the cluster. Previous studies of () MoFeP revealed that when the oxygen-based residue, βSer188, was mutated to a noncoordinating residue, Ala, the P-cluster became redox-labile and reversibly lost two of its eight Fe centers. Surprisingly, the strain with a MoFeP variant that lacked the serine ligand ( βSer188Ala MoFeP) displayed the same diazotrophic growth and enzyme turnover rates as wild-type MoFeP, calling into question the necessity of this conserved ligand for nitrogenase function. Based on these observations, we hypothesized that βSer188 plays a role in protecting the P-cluster under nonideal conditions. Here, we investigated the protective role of βSer188 both and by characterizing the ability of βSer188Ala cells to grow under suboptimal conditions (high oxidative stress or Fe limitation) and by determining the tendency of βSer188Ala MoFeP to be mismetallated . Our results demonstrate that βSer188 (1) increases cell survival upon exposure to oxidative stress in the form of hydrogen peroxide, (2) is necessary for efficient diazotrophic growth under Fe-limiting conditions, and (3) may protect the P-cluster from metal exchange . Taken together, our findings suggest a structural adaptation of nitrogenase to protect the P-cluster via Ser ligation, which is a previously unidentified functional role of the Ser residue in redox proteins and adds to the expanding functional roles of non-Cys ligands to FeS clusters.

PubMed: 36445204
DOI: 10.1021/jacs.2c09480

実験手法

X-RAY DIFFRACTION (2 Å)