PDBsum entry 2ix6

Oxidoreductase

PDB id: 2ix6

Contents

Protein chains

(+ 0 more) 417 a.a. *

Ligands

FAD ×6

* Residue conservation analysis

PDB id:

2ix6

Name:

Oxidoreductase

Title:

Short chain specific acyl-coa oxidase from arabidopsis thaliana, acx4

Structure:

Acyl-coenzyme a oxidase 4, peroxisomal. Chain: a, b, c, d, e, f. Synonym: acyl-coa oxidase, aox 4, short-chain acyl-coa oxidase, saox, atcx4, g6p, atg6. Engineered: yes

Source:

Arabidopsis thaliana. Mouse-ear cress. Organism_taxid: 3702. Expressed in: escherichia coli. Expression_system_taxid: 469008. Other_details: arabidopsis biological resource center

Biol. unit:

Tetramer (from PDB file)

Resolution:

3.90Å R-factor: 0.247 R-free: 0.251

Authors:

J.Mackenzie,L.Pedersen,S.Arent,A.Henriksen

Key ref:

J.Mackenzie et al. (2006). Controlling electron transfer in Acyl-CoA oxidases and dehydrogenases: a structural view. J Biol Chem, 281, 31012-31020. PubMed id: 16887802 DOI: 10.1074/jbc.M603405200

Date:

07-Jul-06 Release date: 08-Aug-06

Protein chains

Q96329  (ACOX4_ARATH) -  Acyl-coenzyme A oxidase 4, peroxisomal from Arabidopsis thaliana

Seq: 436 a.a.

Struc: 417 a.a.

Enzyme reactions

• Enzyme class: E.C.1.3.3.6 - acyl-CoA oxidase.
• Reaction: a 2,3-saturated acyl-CoA + O2 = a (2E)-enoyl-CoA + H2O2
• Cofactor: FAD

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

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

reference

DOI no: 10.1074/jbc.M603405200

J Biol Chem 281:31012-31020 (2006)

PubMed id: 16887802

Controlling electron transfer in Acyl-CoA oxidases and dehydrogenases: a structural view.

J.Mackenzie, L.Pedersen, S.Arent, A.Henriksen.

ABSTRACT

Plants produce a unique peroxisomal short chain-specific acyl-CoA oxidase (ACX4) for beta-oxidation of lipids. The short chain-specific oxidase has little resemblance to other peroxisomal acyl-CoA oxidases but has an approximately 30% sequence identity to mitochondrial acyl-CoA dehydrogenases. Two biochemical features have been linked to structural properties by comparing the structures of short chain-specific Arabidopsis thaliana ACX4 with and without a substrate analogue bound in the active site to known acyl-CoA oxidases and dehydrogenase structures: (i) a solvent-accessible acyl binding pocket is not required for oxygen reactivity, and (ii) the oligomeric state plays a role in substrate pocket architecture but is not linked to oxygen reactivity. The structures indicate that the acyl-CoA oxidases may encapsulate the electrons for transfer to molecular oxygen by blocking the dehydrogenase substrate interaction site with structural extensions. A small binding pocket observed adjoining the flavin adenine dinucleotide N5 and C4a atoms could increase the number of productive encounters between flavin adenine dinucleotide and O2.

Selected figure(s)

Figure 2.
FIGURE 2. The role of the N-and C-terminal tails of ACX4 in burying the FAD cofactor. The N terminus of subunit B (green) and the C terminus of subunit C (tan) are made transparent to show how they enclose the FAD cofactor.

Figure 3.
FIGURE 3. Superposition of A. thaliana ACX1 (green and gray) and ACX4 (beige and black) dimer. The N-terminal extension of ACX4 (red) covering the electron transfer flavoproteins docking area of ACDs is superposable on the C terminus of ACX1 (orange).

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2006, 281, 31012-31020) copyright 2006.

Figures were selected by an automated process.