4RWM

Kuenenia stuttgartiensis hydroxylamine oxidoreductase cryoprotected with ethylene glycol

Summary for 4RWM

• Entry DOI: 10.2210/pdb4rwm/pdb
• Related: 4N4J
• Descriptor: Similar to hydroxylamine oxidoreductase hao, PHOSPHATE ION, 1,2-ETHANEDIOL, ... (6 entities in total)
• Functional Keywords: oxidoreductase, p468 cofactor
• Biological source: Candidatus Kuenenia stuttgartiensis
• Total number of polymer chains: 1
• Total formula weight: 62464.39

Authors

Dietl, A.,Maalcke, W.,Barends, T.R.M. (deposition date: 2014-12-05, release date: 2015-08-12, Last modification date: 2024-11-06)

Primary citation

Dietl, A.,Maalcke, W.,Barends, T.R.
An unexpected reactivity of the P460 cofactor in hydroxylamine oxidoreductase.
Acta Crystallogr. D Biol. Crystallogr., 71:1708-1713, 2015

PubMed Abstract: Hydroxylamine oxidoreductases (HAOs) contain a unique haem cofactor called P460 that consists of a profoundly ruffled c-type haem with two covalent bonds between the haem porphyrin and a conserved tyrosine. This cofactor is exceptional in that it abstracts electrons from a ligand bound to the haem iron, whereas other haems involved in redox chemistry usually inject electrons into their ligands. The effects of the tyrosine cross-links and of the haem ruffling on the chemistry of this cofactor have been investigated theoretically but are not yet clear. A new crystal structure of an HAO from Candidatus Kuenenia stuttgartiensis, a model organism for anaerobic ammonium oxidation, now shows that its P460 cofactor has yet another unexpected reactivity: when ethylene glycol was used as a cryoprotectant, the 1.8 Å resolution electron-density maps showed additional density which could be interpreted as an ethylene glycol molecule covalently bound to the C16 atom of the haem ring, opposite the covalent links to the conserved tyrosine. Possible causes for this unexpected reactivity are discussed.

PubMed: 26249351
DOI: 10.1107/S1399004715010706

Experimental method

X-RAY DIFFRACTION (1.8 Å)