5B82

Crystal structure of the cyanobacterial heme-protein Tll0287

5B82 の概要

• エントリーDOI: 10.2210/pdb5b82/pdb
• 分子名称: Tll0287 protein, HEME C, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: pas domain, hemec, photosystem ii, photosynthesis
• 由来する生物種: Thermosynechococcus elongatus (strain BP-1)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 21837.17

構造登録者

Suga, M.,Motomura, T.,Shen, J.R. (登録日: 2016-06-12, 公開日: 2017-05-03, 最終更新日: 2024-10-23)

主引用文献

Motomura, T.,Suga, M.,Hienerwadel, R.,Nakagawa, A.,Lai, T.L.,Nitschke, W.,Kuma, T.,Sugiura, M.,Boussac, A.,Shen, J.R.
Crystal structure and redox properties of a novel cyanobacterial heme protein with a His/Cys heme axial ligation and a Per-Arnt-Sim (PAS)-like domain
J. Biol. Chem., 292:9599-9612, 2017

PubMed Abstract: Photosystem II catalyzes light-induced water oxidation leading to the generation of dioxygen indispensable for sustaining aerobic life on Earth. The Photosystem II reaction center is composed of D1 and D2 proteins encoded by and genes, respectively. In cyanobacteria, different genes are present in the genome. The thermophilic cyanobacterium contains three genes: , , and , and a new -type heme protein, Tll0287, was found to be expressed in a strain expressing the gene only, but the structure and function of Tll0287 are unknown. Here we solved the crystal structure of Tll0287 at a 2.0 Å resolution. The overall structure of Tll0287 was found to be similar to some kinases and sensor proteins with a Per-Arnt-Sim-like domain rather than to other -type cytochromes. The fifth and sixth axial ligands for the heme were Cys and His, instead of the His/Met or His/His ligand pairs observed for most of the -type hemes. The redox potential, , of Tll0287 was -255 ± 20 mV normal hydrogen electrode at pH values above 7.5. Below this pH value, the increased by ≈57 mV/pH unit at 15 °C, suggesting the involvement of a protonatable group with a p = 7.2 ± 0.3. Possible functions of Tll0287 as a redox sensor under microaerobic conditions or a cytochrome subunit of an HS-oxidizing system are discussed in view of the environmental conditions in which is expressed, as well as phylogenetic analysis, structural, and sequence homologies.

PubMed: 28428249
DOI: 10.1074/jbc.M116.746263

実験手法

X-RAY DIFFRACTION (2 Å)