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

Citation

Sundaramoorthy, R and Micossi, E and Alphey, MS and Germain, V and Bryce, JH and Smith, SM and Leonard, GA and Hunter, WN, The crystal structure of a plant 3-ketoacyl-CoA thiolase reveals the potential for redox control of peroxisomal fatty acid β-oxidation, Journal of Molecular Biology, 359, (2) pp. 347-357. ISSN 0022-2836 (2006) [Refereed Article]


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DOI: doi:10.1016/j.jmb.2006.03.032

Abstract

Crystal structures of peroxisomal Arabidopsis thaliana 3-ketoacyl-CoA thiolase (AtKAT), an enzyme of fatty acid β-oxidation, are reported. The subunit, a typical thiolase, is a combination of two similar α/β 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 α-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 β-oxidation with redox regulation.

Item Details

Item Type:Refereed Article
Keywords:arabidopsis thaliana, 3-ketoacyl-CoA thiolase, fatty acid beta-oxidation
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Biological Sciences
Author:Smith, SM (Professor Steven Smith)
ID Code:101513
Year Published:2006
Web of Science® Times Cited:15
Deposited By:Plant Science
Deposited On:2015-06-25
Last Modified:2017-11-23
Downloads:0

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