| Structural highlights
Function
[THIK2_ARATH] Involved in long chain fatty-acid beta-oxidation prior to gluconeogenesis during germination and subsequent seedling growth. Confers sensitivity to 2,4-dichlorophenoxybutiric acid (2,4-DB). Required for local and systemic induction of jasmonic acid (JA) biosynthesis after wounding. Seems to be involved in JA biosynthesis during senescence.[1] [2] [3] [4] [5]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
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.
The crystal structure of a plant 3-ketoacyl-CoA thiolase reveals the potential for redox control of peroxisomal fatty acid beta-oxidation.,Sundaramoorthy R, Micossi E, Alphey MS, Germain V, Bryce JH, Smith SM, Leonard GA, Hunter WN J Mol Biol. 2006 Jun 2;359(2):347-57. Epub 2006 Mar 29. PMID:16630629[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Hayashi M, Toriyama K, Kondo M, Nishimura M. 2,4-Dichlorophenoxybutyric acid-resistant mutants of Arabidopsis have defects in glyoxysomal fatty acid beta-oxidation. Plant Cell. 1998 Feb;10(2):183-95. PMID:9490742
- ↑ Germain V, Rylott EL, Larson TR, Sherson SM, Bechtold N, Carde JP, Bryce JH, Graham IA, Smith SM. Requirement for 3-ketoacyl-CoA thiolase-2 in peroxisome development, fatty acid beta-oxidation and breakdown of triacylglycerol in lipid bodies of Arabidopsis seedlings. Plant J. 2001 Oct;28(1):1-12. PMID:11696182
- ↑ He Y, Fukushige H, Hildebrand DF, Gan S. Evidence supporting a role of jasmonic acid in Arabidopsis leaf senescence. Plant Physiol. 2002 Mar;128(3):876-84. PMID:11891244 doi:http://dx.doi.org/10.1104/pp.010843
- ↑ Cruz Castillo M, Martinez C, Buchala A, Metraux JP, Leon J. Gene-specific involvement of beta-oxidation in wound-activated responses in Arabidopsis. Plant Physiol. 2004 May;135(1):85-94. PMID:15141068 doi:http://dx.doi.org/10.1104/pp.104.039925
- ↑ Afitlhile MM, Fukushige H, Nishimura M, Hildebrand DF. A defect in glyoxysomal fatty acid beta-oxidation reduces jasmonic acid accumulation in Arabidopsis. Plant Physiol Biochem. 2005 Jun;43(6):603-9. PMID:15979881 doi:http://dx.doi.org/S0981-9428(05)00126-9
- ↑ Sundaramoorthy R, Micossi E, Alphey MS, Germain V, Bryce JH, Smith SM, Leonard GA, Hunter WN. 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. 2006 Jun 2;359(2):347-57. Epub 2006 Mar 29. PMID:16630629 doi:http://dx.doi.org/10.1016/j.jmb.2006.03.032
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