1HZU

DOMAIN SWING UPON HIS TO ALA MUTATION IN NITRITE REDUCTASE OF PSEUDOMONAS AERUGINOSA

1HZU の概要

• エントリーDOI: 10.2210/pdb1hzu/pdb
• 分子名称: NITRITE REDUCTASE, HEME C, HEME D, ... (4 entities in total)
• 機能のキーワード: cytochrome c, 8 bladed beta propeller, oxidoreductase
• 由来する生物種: Pseudomonas aeruginosa
• 細胞内の位置: Periplasm: P24474
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 61522.97

構造登録者

Brown, K.,Cutruzzola, F.,Brunori, M.,Tegoni, M.,Cambillau, C. (登録日: 2001-01-26, 公開日: 2001-09-26, 最終更新日: 2024-11-20)

主引用文献

Brown, K.,Roig-Zamboni, V.,Cutruzzola, F.,Arese, M.,Sun, W.,Brunori, M.,Cambillau, C.,Tegoni, M.
Domain swing upon His to Ala mutation in nitrite reductase of Pseudomonas aeruginosa.
J.Mol.Biol., 312:541-554, 2001

PubMed Abstract: The nitrite reductase (NIR) from Pseudomonas aeruginosa (NIR-Pa) is a soluble enzyme catalysing the reduction of nitrite (NO2(-)) to nitric oxide (NO). The enzyme is a 120 kDa homodimer, in which the monomers carry a c-heme domain and a d(1)-heme domain. The structures of the enzyme in both the oxidised and reduced state were solved previously and indicate His327 and His369 as putative catalytic residues. The kinetic characterisation of site-directed mutants has shown that the substitution of either one of these two His with Ala dramatically reduces the physiologically relevant reactivity towards nitrite, leaving the reactivity towards oxygen unaffected. The three-dimensional structures of P. aeruginosa NIR mutant H327A, and H369A in complex with NO have been solved by multiple wavelength anomalous dispersion (MAD), using the iron anomalous signal, and molecular replacement techniques. In both refined crystal structures the c-heme domain, whilst preserving its classical c-type cytochrome fold, has undergone a 60 degrees rigid-body rotation around an axis parallel with the pseudo 8-fold axis of the beta-propeller, and passing through residue Gln115. Even though the distance between the Fe ions of the c and d(1)-heme remains 21 A, the edge-to-edge distance between the two hemes has increased by 5 A. Furthermore the distal side of the d(1)-heme pocket appears to have undergone structural re-arrangement and Tyr10 has moved out of the active site. In the H369A-NO complex, the position and orientation of NO is significantly different from that of the NO bound to the reduced wild-type structure. Our results provide insight into the flexibility of the enzyme and the distinction between nitrite and oxidase reduction mechanisms. Moreover they demonstrate that the two histidine residues play a crucial role in the physiological activity of nitrite reduction, ligand binding and in the structural organisation of nitrite reductase from P. aeruginosa.

PubMed: 11563915
DOI: 10.1006/jmbi.2001.4986

実験手法

X-RAY DIFFRACTION (2.7 Å)