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Acyl-lipid thioesterase1- from Arabidopsis thaliana form a novel family of fatty acyl–acyl carrier protein thioesterases with divergent expression patterns and substrate specificities
- 作者:Ian P. Pulsifer (1)
Christine Lowe (1) Swara A. Narayaran (1) Alia S. Busuttil (1) Sollapura J. Vishwanath (1) Frédéric Domergue (2) Owen Rowland (1)
- 关键词:Arabidopsis thaliana ; Thioesterase ; Plastid ; Acyl carrier protein ; Fatty acid ; Methylketone
- 刊名:Plant Molecular Biology
- 出版年:2014
- 出版时间:March 2014
- 年:2014
- 卷:84
- 期:4-5
- 页码:549-563
- 全文大小:2,130 KB
- 作者单位:Ian P. Pulsifer (1)
Christine Lowe (1) Swara A. Narayaran (1) Alia S. Busuttil (1) Sollapura J. Vishwanath (1) Frédéric Domergue (2) Owen Rowland (1)
1. Department of Biology, Institute of Biochemistry, Carleton University, Ottawa, ON, K1S 5B6, Canada 2. Laboratoire de Biogenèse Membranaire, Université Bordeaux Ségalen, CNRS-UMR 5200, Batiment A3-INRA Bordeaux Aquitaine BP81, 71 Avenue Edouard Bourlaux, 33883, Villenave D’Ornon Cedex, France
- ISSN:1573-5028
文摘
Hydrolysis of fatty acyl thioester bonds by thioesterases to produce free fatty acids is important for dictating the diversity of lipid metabolites produced in plants. We have characterized a four-member family of fatty acyl thioesterases from Arabidopsis thaliana, which we have called acyl-lipid thioesterase1 (ALT1), ALT2, ALT3, and ALT4. The ALTs belong to the Hotdog fold superfamily of thioesterases. ALT-like genes are present in diverse plant taxa, including dicots, monocots, lycophytes, and microalgae. The four Arabidopsis ALT genes were found to have distinct gene expression profiles with respect to each other. ALT1 was expressed specifically in stem epidermal cells and flower petals. ALT2 was expressed specifically in root endodermal and peridermal cells as well as in stem lateral organ boundary cells. ALT3 was ubiquitously expressed in aerial and root tissues and at much higher levels than the other ALTs. ALT4 expression was restricted to anthers. All four proteins were localized in plastids via an N-terminal targeting sequence of about 48 amino acids. When expressed in Escherichia coli, the ALT proteins used endogenous fatty acyl–acyl carrier protein substrates to generate fatty acids that varied in chain length (C6–C18), degree of saturation (saturated and monounsaturated), and oxidation state (fully reduced and β-ketofatty acids). Despite their high amino acid sequence identities, each enzyme produced a different profile of lipids in E. coli. The biological roles of these proteins are unknown, but they potentially generate volatile lipid metabolites that have previously not been reported in Arabidopsis.
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