PDBsum entry 2c7z

Transferase

PDB id: 2c7z

Contents

Protein chain

396 a.a. *

Waters ×102

* Residue conservation analysis

PDB id:

2c7z

Name:

Transferase

Title:

Plant enzyme crystal form ii

Structure:

3-ketoacyl-coa thiolase 2. Chain: a. Fragment: residues 38-441. Synonym: beta-ketothiolase 2, acetyl-coa acyltransferase 2, peroxisomal 3-oxoacyl-coa thiolase 2, peroxisome defective protein 1. Engineered: yes

Source:

Arabidopsis thaliana. Mouse-ear cress. Organism_taxid: 3702. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Biol. unit:

Dimer (from PDB file)

Resolution:

2.37Å R-factor: 0.202 R-free: 0.276

Authors:

R.Sundaramoorthy,E.Micossi,M.S.Alphey,G.A.Leonard,W.N.Hunter

Key ref:

R.Sundaramoorthy et al. (2006). The crystal structure of a plant 3-ketoacyl-CoA thiolase reveals the potential for redox control of peroxisomal fatty acid beta-oxidation. J Mol Biol, 359, 347-357. PubMed id: 16630629 DOI: 10.1016/j.jmb.2006.03.032

Date:

30-Nov-05 Release date: 17-May-06

Protein chain

Q56WD9  (THIK2_ARATH) -  3-ketoacyl-CoA thiolase 2, peroxisomal from Arabidopsis thaliana

Seq: 462 a.a.

Struc: 396 a.a.

Enzyme reactions

• Enzyme class: E.C.2.3.1.16 - acetyl-CoA C-acyltransferase.
• Reaction: an acyl-CoA + acetyl-CoA = a 3-oxoacyl-CoA + CoA

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

reference

DOI no: 10.1016/j.jmb.2006.03.032

J Mol Biol 359:347-357 (2006)

PubMed id: 16630629

The crystal structure of a plant 3-ketoacyl-CoA thiolase reveals the potential for redox control of peroxisomal fatty acid beta-oxidation.

R.Sundaramoorthy, E.Micossi, M.S.Alphey, V.Germain, J.H.Bryce, S.M.Smith, G.A.Leonard, W.N.Hunter.

ABSTRACT

Crystal structures of peroxisomal Arabidopsis thaliana 3-ketoacyl-CoA thiolase (AtKAT), an enzyme of fatty acid beta-oxidation, are reported. The subunit, a typical thiolase, is a combination of two similar alpha/beta domains capped with a loop domain. The comparison of AtKAT with the Saccharomyces cerevisiae homologue (ScKAT) structure reveals a different placement of subunits within the functional dimers and that a polypeptide segment forming an extended loop around the open catalytic pocket of ScKAT converts to alpha-helix in AtKAT, and occludes the active site. A disulfide is formed between Cys192, on this helix, and Cys138, a catalytic residue. Access to Cys138 is determined by the structure of this polypeptide segment. AtKAT represents an oxidized, previously unknown inactive form, whilst ScKAT is the reduced and active enzyme. A high level of sequence conservation is observed, including Cys192, in eukaryotic peroxisomal, but not mitochondrial or prokaryotic KAT sequences, for this labile loop/helix segment. This indicates that KAT activity in peroxisomes is influenced by a disulfide/dithiol change linking fatty acid beta-oxidation with redox regulation.

Selected figure(s)

Figure 3.
Figure 3. Structural overlay of AtKAT (red) and ScKAT (grey) dimers based on the least-squares fit of a single subunit A. Helices are depicted as cylinders, β-strands as arrows. Figure 3. Structural overlay of AtKAT (red) and ScKAT (grey) dimers based on the least-squares fit of a single subunit A. Helices are depicted as cylinders, β-strands as arrows.

Figure 4.
Figure 4. Active site details. AtKAT sections are shown in stick-mode with atomic positions, C colored grey, N blue, O red and S orange, with hydrogen bonding interactions (distances <3.4 Å) as blue broken lines. (a) Hydrogen bonding associated with a buried water molecule, a blue sphere, which binds Cys425. (b) The environment of His393. Helix α4 is depicted as a yellow ribbon. Figure 4. Active site details. AtKAT sections are shown in stick-mode with atomic positions, C colored grey, N blue, O red and S orange, with hydrogen bonding interactions (distances <3.4 Å) as blue broken lines. (a) Hydrogen bonding associated with a buried water molecule, a blue sphere, which binds Cys425. (b) The environment of His393. Helix α4 is depicted as a yellow ribbon.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2006, 359, 347-357) copyright 2006.

Figures were selected by the author.