Hydroxylamine oxidoreductase (HAO) from Nitrosomonas europaea is a homotrimeric protein that catalyzes the oxidation of hydroxylamine to nitrite. Each monomer, with a molecular weight of 67.1 kDa, contains seven c-type hemes and one heme P460, the porphyrin ring of which is covalently linked to a tyrosine residue from an adjacent subunit. HAO was first crystallized and structurally characterized at a resolution of 2.8 Å in 1997. The structure was solved in space group P63 and suffered from merohedral twinning. Here, a crystallization procedure is presented that yielded untwinned crystals belonging to space group P21212, which diffracted to 2.25 Å resolution and contained one trimer in the asymmetric unit. The unit-cell parameters were a = 140.7, b = 142.6, c = 107.4 Å.
|Original language||English (US)|
|Number of pages||3|
|Journal||Acta Crystallographica Section F: Structural Biology and Crystallization Communications|
|State||Published - Dec 1 2009|
- Heme P460
- Hydroxylamine oxidoreductase