5VQ3

Nitrogenase Cp1 at pH 6.5

5VQ3 の概要

• エントリーDOI: 10.2210/pdb5vq3/pdb
• 関連するPDBエントリー: 5VPW 5VQ4
• 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: nitrogenase, molybdenum-iron protein, mofe protein, cp1, oxidoreductase
• 由来する生物種: Clostridium pasteurianum; 詳細
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 219533.43

構造登録者

Morrison, C.N.,Spatzal, T.,Rees, D.C. (登録日: 2017-05-07, 公開日: 2017-07-26, 最終更新日: 2023-10-04)

主引用文献

Morrison, C.N.,Spatzal, T.,Rees, D.C.
Reversible Protonated Resting State of the Nitrogenase Active Site.
J. Am. Chem. Soc., 139:10856-10862, 2017

PubMed Abstract: Protonated states of the nitrogenase active site are mechanistically significant since substrate reduction is invariably accompanied by proton uptake. We report the low pH characterization by X-ray crystallography and EPR spectroscopy of the nitrogenase molybdenum iron (MoFe) proteins from two phylogenetically distinct nitrogenases (Azotobacter vinelandii, Av, and Clostridium pasteurianum, Cp) at pHs between 4.5 and 8. X-ray data at pHs of 4.5-6 reveal the repositioning of side chains along one side of the FeMo-cofactor, and the corresponding EPR data shows a new S = 3/2 spin system with spectral features similar to a state previously observed during catalytic turnover. The structural changes suggest that FeMo-cofactor belt sulfurs S3A or S5A are potential protonation sites. Notably, the observed structural and electronic low pH changes are correlated and reversible. The detailed structural rearrangements differ between the two MoFe proteins, which may reflect differences in potential protonation sites at the active site among nitrogenase species. These observations emphasize the benefits of investigating multiple nitrogenase species. Our experimental data suggest that reversible protonation of the resting state is likely occurring, and we term this state "EH", following the Lowe-Thorneley naming scheme.

PubMed: 28692802
DOI: 10.1021/jacs.7b05695

実験手法

X-RAY DIFFRACTION (1.72 Å)