2VXX

X-ray structure of DpsA from Thermosynechococcus elongatus

2VXX の概要

• エントリーDOI: 10.2210/pdb2vxx/pdb
• 分子名称: STARVATION INDUCED DNA BINDING PROTEIN, ZINC ION, FE (III) ION, ... (6 entities in total)
• 機能のキーワード: stress response protein, dna-binding protein, dps, oxidation, iron binding, ferroxidase centre, dna binding protein
• 由来する生物種: SYNECHOCOCCUS ELONGATUS
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 87657.51

構造登録者

Franceschini, S.,Ilari, A. (登録日: 2008-07-14, 公開日: 2009-11-17, 最終更新日: 2023-12-13)

主引用文献

Alaleona, F.,Franceschini, S.,Ceci, P.,Ilari, A.,Chiancone, E.
Thermosynechococcus Elongatus Dpsa Binds Zn(II) at a Unique Three Histidine-Containing Ferroxidase Center and Utilizes O2 as Iron Oxidant with Very High Efficiency, Unlike the Typical Dps Proteins.
FEBS J., 277:903-, 2010

PubMed Abstract: The cyanobacterium Thermosynechococcus elongatus is one the few bacteria to possess two Dps proteins, DpsA-Te and Dps-Te. The present characterization of DpsA-Te reveals unusual structural and functional features that differentiate it from Dps-Te and the other known Dps proteins. Notably, two Zn(II) are bound at the ferroxidase center, owing to the unique substitution of a metal ligand at the A-site (His78 in place of the canonical aspartate) and to the presence of a histidine (His164) in place of a hydrophobic residue at a metal-coordinating distance in the B-site. Only the latter Zn(II) is displaced by incoming iron, such that Zn(II)-Fe(III) complexes are formed upon oxidation, as indicated by absorbance and atomic emission spectroscopy data. In contrast to the typical behavior of Dps proteins, where Fe(II) oxidation by H(2)O(2) is about 100-fold faster than by O(2), in DpsA-Te the ferroxidation efficiency of O(2) is very high and resembles that of H(2)O(2). Oxygraphic experiments show that two Fe(II) are required to reduce O(2), and that H(2)O(2) is not released into solution at the end of the reaction. On this basis, a reaction mechanism is proposed that also takes into account the formation of Zn(II)-Fe(III) complexes. The physiological significance of the DpsA-Te behavior is discussed in the framework of a possible localization of the protein at the thylakoid membranes, where photosynthesis takes place, with the consequent increased formation of reactive oxygen species.

PubMed: 20088882
DOI: 10.1111/J.1742-4658.2009.07532.X

実験手法

X-RAY DIFFRACTION (2.4 Å)