1Z9N

X-Ray structure of a Cu-Zn superoxide dismutase from Haemophilus ducreyi with haem bound at the dimer interface

1Z9N の概要

• エントリーDOI: 10.2210/pdb1z9n/pdb
• 関連するPDBエントリー: 1BZO 1YAI 2APS
• 分子名称: Superoxide dismutase [Cu-Zn], COPPER (II) ION, ZINC ION, ... (5 entities in total)
• 機能のキーワード: cu-zn sod; sod; haem, oxidoreductase
• 由来する生物種: Haemophilus ducreyi
• 細胞内の位置: Periplasm: Q59452
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 78231.86

構造登録者

Djinovic Carugo, K.,Toeroe, I. (登録日: 2005-04-03, 公開日: 2006-09-19, 最終更新日: 2023-08-23)

主引用文献

Toro, I.,Petrutz, C.,Pacello, F.,D'Orazio, M.,Battistoni, A.,Djinovic-Carugo, K.
Structural basis of heme binding in the Cu,Zn superoxide dismutase from Haemophilus ducreyi.
J.Mol.Biol., 386:406-418, 2009

PubMed Abstract: The Cu,Zn superoxide dismutase from Haemophilus ducreyi is characterized by the unique ability to bind heme at its dimer interface. Here we report the high-resolution crystal structures of this protein in the heme-loaded (holo) and heme-free (apo) forms. Heme is asymmetrically bound between the two enzyme subunits, where heme iron is coordinated by two histidine residues, His64 and His 124, provided by the two subunits. Moreover, the binding of heme to the protein is ensured by stabilizing contacts between the prosthetic group and a limited number of other residues, most of which are not present in other bacterial enzyme variants. We show that the introduction of only three mutations at the dimer interface of the enzyme from Haemophilus parainfluenzae, a closely related bacterial species, is sufficient to induce heme-binding ability by this enzyme variant. Heme binding does not alter protein activity. Moreover, the binding of the prosthetic group does not induce any significant structural perturbation at the subunit level and requires only limited local structural rearrangements that widen the cleft at the dimer interface and cause a limited shift in the relative orientation between the subunits. The presence of a preformed heme-binding pocket and the significant solvent exposure of the cofactor to the solvent are compatible with the suggested protective role of the enzyme against heme toxicity or with its involvement in heme trafficking in the periplasmic space.

PubMed: 19103206
DOI: 10.1016/j.jmb.2008.12.004

実験手法

X-RAY DIFFRACTION (1.5 Å)