PDBsum entry 4n4n

Oxidoreductase

PDB id: 4n4n

Contents

Protein chains

504 a.a.

56 a.a.

57 a.a.

Ligands

HEC ×24

PO4

Metals

__K

Waters ×1094

PDB id:

4n4n

Name:

Oxidoreductase

Title:

Nitrosomonas europea hao

Structure:

Hydroxylamine oxidoreductase. Chain: a, c, e. Fragment: unp residues 25-528. Synonym: hao. Hydroxylamine oxidoreductase. Chain: b, d, f. Fragment: unp residues 28-84. Ec: 1.7.2.6

Source:

Nitrosomonas europaea. Organism_taxid: 915. Organism_taxid: 915

Resolution:

2.20Å R-factor: 0.182 R-free: 0.213

Authors:

W.J.Maalcke,A.Dietl,S.J.Marritt,J.N.Butt,M.S.M.Jetten,J.T.Keltjens, T.R.M.B.Barends,B.Kartal

Key ref:

W.J.Maalcke et al. (2014). Structural basis of biological NO generation by octaheme oxidoreductases. J Biol Chem, 289, 1228-1242. PubMed id: 24302732 DOI: 10.1074/jbc.M113.525147

Date:

08-Oct-13 Release date: 11-Dec-13

Protein chains

Q50925  (HAO_NITEU) -  Hydroxylamine oxidoreductase from Nitrosomonas europaea (strain ATCC 19718 / CIP 103999 / KCTC 2705 / NBRC 14298)

Seq: 570 a.a.

Struc: 504 a.a.

Protein chain

Q82V11  (Q82V11_NITEU) -  Secreted protein from Nitrosomonas europaea (strain ATCC 19718 / CIP 103999 / KCTC 2705 / NBRC 14298)

Seq: 91 a.a.

Struc: 56 a.a.

Protein chains

Q82V11  (Q82V11_NITEU) -  Secreted protein from Nitrosomonas europaea (strain ATCC 19718 / CIP 103999 / KCTC 2705 / NBRC 14298)

Seq: 91 a.a.

Struc: 57 a.a.

Enzyme reactions

• Enzyme class 2: Chains A, B, C, D, E, F: E.C.1.7.2.6 - hydroxylamine dehydrogenase.
• Reaction: hydroxylamine + 4 Fe(III)-[cytochrome c] + H2O = 4 Fe(II)-[cytochrome c] + nitrite + 5 H⁺
• Cofactor: Heme

Heme (Bound ligand (Het Group name = HEC) matches with 95.45% similarity)

• Enzyme class 3: Chains A, C, E: E.C.1.7.2.9 - hydroxylamine oxidase.
• Reaction: hydroxylamine + 3 Fe(III)-[cytochrome c] = nitric oxide + 3 Fe(II)- [cytochrome c] + 3 H⁺

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1074/jbc.M113.525147

J Biol Chem 289:1228-1242 (2014)

PubMed id: 24302732

Structural basis of biological NO generation by octaheme oxidoreductases.

W.J.Maalcke, A.Dietl, S.J.Marritt, J.N.Butt, M.S.Jetten, J.T.Keltjens, T.R.Barends, B.Kartal.

ABSTRACT

Nitric oxide is an important molecule in all domains of life with significant biological functions in both pro- and eukaryotes. Anaerobic ammonium-oxidizing (anammox) bacteria that contribute substantially to the release of fixed nitrogen into the atmosphere use the oxidizing power of NO to activate inert ammonium into hydrazine (N2H4). Here, we describe an enzyme from the anammox bacterium Kuenenia stuttgartiensis that uses a novel pathway to make NO from hydroxylamine. This new enzyme is related to octaheme hydroxylamine oxidoreductase, a key protein in aerobic ammonium-oxidizing bacteria. By a multiphasic approach including the determination of the crystal structure of the K. stuttgartiensis enzyme at 1.8 Å resolution and refinement and reassessment of the hydroxylamine oxidoreductase structure from Nitrosomonas europaea, both in the presence and absence of their substrates, we propose a model for NO formation by the K. stuttgartiensis enzyme. Our results expand the understanding of the functions that the widespread family of octaheme proteins have.