1LSX

Crystal structure of the methylimidazole-bound BjFixL heme domain

1LSX の概要

• エントリーDOI: 10.2210/pdb1lsx/pdb
• 関連するPDBエントリー: 1DP6 1DP8 1DP9 1DRM 1LSV 1LSW 1LT0
• 分子名称: Sensor protein FixL, PROTOPORPHYRIN IX CONTAINING FE, 1-METHYLIMIDAZOLE, ... (4 entities in total)
• 機能のキーワード: pas fold, transferase
• 由来する生物種: Bradyrhizobium japonicum
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 15619.46

構造登録者

Hao, B.,Isaza, C.,Arndt, J.,Soltis, M.,Chan, M.K. (登録日: 2002-05-20, 公開日: 2002-11-20, 最終更新日: 2024-02-14)

主引用文献

Hao, B.,Isaza, C.,Arndt, J.,Soltis, M.,Chan, M.K.
Structure-based mechanism of O2 sensing and ligand discrimination by the FixL heme domain of Bradyrhizobium japonicum
Biochemistry, 41:12952-12958, 2002

PubMed Abstract: Structures of the Bradyrhizobium japonicum FixL heme domain have been determined in the absence and presence of specific ligands to elucidate the detailed features of its O2 sensing mechanism. The putative roles of spin-state and steric hindrance were evaluated by the structure determination of ferrous CO-bound BjFixLH and correlating its features with other ligand-bound structures. As found for NO-BjFixLH, no protein conformational change was observed in CO-BjFixLH, suggesting a more complicated mechanism than solely spin state or ligand sterics. To evaluate the role of oxidation state, the structure of the ferrous deoxy-BjFixLH was determined. The structure of deoxy-BjFixLH was found to be virtually identical to the structure of the ferric met-BjFixLH. The role of hydrogen bonding of substrates to a heme-pocket water was evaluated by determining the structure of BjFixLH bound to 1-methyl-imidazole that cannot form a hydrogen bond with this water. In this case, the heme-mediated conformational change was observed, limiting the potential importance of this interaction. Finally, the structure of cyanomet-BjFixLH was revisited to rule out concerns regarding the partial occupancy of the cyanide ligand in a previous structure. In the revised structure, Arg 220 was found to move into the heme pocket to form a hydrogen bond to the bound cyanide ligand. The implications of these results on FixL's sensing mechanism are discussed.

PubMed: 12390021
DOI: 10.1021/bi020144l

実験手法

X-RAY DIFFRACTION (2.7 Å)