2ZZL

Structure of bacteriorhodopsin's M intermediate at pH 7

2ZZL の概要

• エントリーDOI: 10.2210/pdb2zzl/pdb
• 関連するPDBエントリー: 1iw6 1iw9
• 分子名称: Bacteriorhodopsin, 3-O-sulfo-beta-D-galactopyranose-(1-6)-alpha-D-mannopyranose-(1-2)-alpha-D-glucopyranose, RETINAL, ... (8 entities in total)
• 機能のキーワード: retinal, protein-lipid complex, reaction intermediate, cell membrane, chromophore, hydrogen ion transport, ion transport, membrane, photoreceptor protein, pyrrolidone carboxylic acid, receptor, retinal protein, sensory transduction, transmembrane, transport, proton transport
• 由来する生物種: Halobacterium salinarum
• 細胞内の位置: Cell membrane; Multi-pass membrane protein: P02945
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 33185.20

構造登録者

Yamamoto, M.,Kouyama, T. (登録日: 2009-02-18, 公開日: 2009-10-06, 最終更新日: 2023-11-01)

主引用文献

Yamamoto, M.,Hayakawa, N.,Murakami, M.,Kouyama, T.
Crystal Structures of Different Substates of Bacteriorhodopsin's M Intermediate at Various pH Levels.
J.Mol.Biol., 2009

PubMed Abstract: The hexagonal P622 crystal of bacteriorhodopsin, which is made up of stacked membranes, is stable provided that the precipitant concentration in the soaking solution is higher than a critical value (i.e., 1.5 M ammonium sulfate). Diffraction data showed that the crystal lattice shrank linearly with increasing precipitant concentration, due primarily to narrowing of intermembrane spaces. Although the crystal shrinkage did not affect the rate of formation of the photoreaction M intermediate, its lifetime increased exponentially with the precipitant concentration. It was suggested that the energetic barrier of the M-to-N transition becomes higher when the motional freedom of the EF loop is reduced by crystal lattice force. As a result of this property, the M state accumulated predominantly when the crystal that was soaked at a high precipitant concentration was illuminated at room temperature. Structural data obtained at various pH levels showed that the overall structure of M is not strongly dependent on pH, except that Glu194 and Glu204 in the proton release complex are more separated at pH 7 than at pH 4.4. This result suggests that light-induced disruption of the paired structure of Glu194 and Glu204 is incomplete when external pH is lower than the pK(a) value of the proton release group in the M state.

PubMed: 19712684
DOI: 10.1016/j.jmb.2009.08.047

実験手法

X-RAY DIFFRACTION (2.03 Å)