4N7L

Zinc Substituted Reaction Center M(L214H) Variant of Rhodobacter sphaeroides

4N7L の概要

• エントリーDOI: 10.2210/pdb4n7l/pdb
• 関連するPDBエントリー: 4N7K
• 分子名称: Reaction center protein H chain, HEPTANE-1,2,3-TRIOL, FE (III) ION, ... (15 entities in total)
• 機能のキーワード: photosynthesis
• 由来する生物種: Rhodobacter sphaeroides; 詳細
• 細胞内の位置: Cellular chromatophore membrane; Single-pass membrane protein: P0C0Y7; Cellular chromatophore membrane; Multi-pass membrane protein: P0C0Y8 P0C0Y9
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 104935.93

構造登録者

Hardjasa, A.,Murphy, M.E.P. (登録日: 2013-10-15, 公開日: 2014-01-22, 最終更新日: 2024-02-28)

主引用文献

Saer, R.G.,Pan, J.,Hardjasa, A.,Lin, S.,Rosell, F.,Mauk, A.G.,Woodbury, N.W.,Murphy, M.E.,Beatty, J.T.
Structural and kinetic properties of Rhodobacter sphaeroides photosynthetic reaction centers containing exclusively Zn-coordinated bacteriochlorophyll as bacteriochlorin cofactors.
Biochim.Biophys.Acta, 1837:366-374, 2014

PubMed Abstract: The Zn-BChl-containing reaction center (RC) produced in a bchD (magnesium chelatase) mutant of Rhodobacter sphaeroides assembles with six Zn-bacteriochlorophylls (Zn-BChls) in place of four Mg-containing bacteriochlorophylls (BChls) and two bacteriopheophytins (BPhes). This protein presents unique opportunities for studying biological electron transfer, as Zn-containing chlorins can exist in 4-, 5-, and (theoretically) 6-coordinate states within the RC. In this paper, the electron transfer perturbations attributed exclusively to coordination state effects are separated from those attributed to the presence, absence, or type of metal in the bacteriochlorin at the HA pocket of the RC. The presence of a 4-coordinate Zn(2+) ion in the HA bacteriochlorin instead of BPhe results in a small decrease in the rates of the P*→P(+)HA(-)→P(+)QA(-) electron transfer, and the charge separation yield is not greatly perturbed; however coordination of the Zn(2+) by a fifth ligand provided by a histidine residue results in a larger rate decrease and yield loss. We also report the first crystal structure of a Zn-BChl-containing RC, confirming that the HA Zn-BChl was either 4- or 5-coordinate in the two types of Zn-BChl-containing RCs studied here. Interestingly, a large degree of disorder, in combination with a relatively weak anomalous difference electron density was found in the HB pocket. These data, in combination with spectroscopic results, indicate partial occupancy of this binding pocket. These findings provide insights into the use of BPhe as the bacteriochlorin pigment of choice at HA in both BChl- and Zn-BChl-containing RCs found in nature.

PubMed: 24316146
DOI: 10.1016/j.bbabio.2013.11.015

実験手法

X-RAY DIFFRACTION (2.85 Å)