PDBsum entry 3d9d

Oxidoreductase

PDB id: 3d9d

Contents

Protein chains

432 a.a. *

Ligands

FAD ×4

N6C ×4

GOL ×8

Waters ×650

* Residue conservation analysis

PDB id:

3d9d

Name:

Oxidoreductase

Title:

Nitroalkane oxidase: mutant d402n crystallized with 1-nitrohexane

Structure:

Nitroalkane oxidase. Chain: a, b, c, d. Engineered: yes. Mutation: yes

Source:

Fusarium oxysporum. Organism_taxid: 5507. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.10Å R-factor: 0.182 R-free: 0.219

Authors:

A.Heroux,D.M.Bozinovski,M.P.Valley,P.F.Fitzpatrick,A.M.Orville

Key ref:

A.Héroux et al. (2009). Crystal structures of intermediates in the nitroalkane oxidase reaction. Biochemistry, 48, 3407-3416. PubMed id: 19265437

Date:

27-May-08 Release date: 07-Apr-09

Protein chains

Q8X1D8  (NAO_FUSOX) -  Nitroalkane oxidase from Fusarium oxysporum

Seq: 439 a.a.

Struc: 432 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.1.7.3.1 - nitroalkane oxidase.
• Reaction:
  1. a primary nitroalkane + O2 + H2O = an aldehyde + nitrite + H2O2 + H⁺
  2. a secondary nitroalkane + O2 + H2O = a ketone + nitrite + H2O2 + H⁺
• Cofactor: FAD

FAD (Bound ligand (Het Group name = FAD) corresponds exactly)

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

reference

Biochemistry 48:3407-3416 (2009)

PubMed id: 19265437

Crystal structures of intermediates in the nitroalkane oxidase reaction.

A.Héroux, D.M.Bozinovski, M.P.Valley, P.F.Fitzpatrick, A.M.Orville.

ABSTRACT

The flavoenzyme nitroalkane oxidase is a member of the acyl-CoA dehydrogenase superfamily. Nitroalkane oxidase catalyzes the oxidation of neutral nitroalkanes to nitrite and the corresponding aldehydes or ketones. Crystal structures to 2.2 A resolution or better of enzyme complexes with bound substrates and of a trapped substrate-flavin adduct are described. The D402N enzyme has no detectable activity with neutral nitroalkanes [Valley, M. P., and Fitzpatrick, P. F. (2003) J. Am. Chem. Soc. 125, 8738-8739]. The structure of the D402N enzyme crystallized in the presence of 1-nitrohexane or 1-nitrooctane shows the presence of the substrate in the binding site. The aliphatic chain of the substrate extends into a tunnel leading to the enzyme surface. The oxygens of the substrate nitro group interact both with amino acid residues and with the 2'-hydroxyl of the FAD. When nitroalkane oxidase oxidizes nitroalkanes in the presence of cyanide, an electrophilic flavin imine intermediate can be trapped [Valley, M. P., Tichy, S. E., and Fitzpatrick, P. F. (2005) J. Am. Chem. Soc. 127, 2062-2066]. The structure of the enzyme trapped with cyanide during oxidation of 1-nitrohexane shows the presence of the modified flavin. A continuous hydrogen bond network connects the nitrogen of the CN-hexyl-FAD through the FAD 2'-hydroxyl to a chain of water molecules extending to the protein surface. Together, our complementary approaches provide strong evidence that the flavin cofactor is in the appropriate oxidation state and correlates well with the putative intermediate state observed within each of the crystal structures. Consequently, these results provide important structural descriptions of several steps along the nitroalkane oxidase reaction cycle.