A phosphopantetheinyl transferase that is essential for mitochondrial fatty acid biosynthesis

Date
2015-11
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Guan, Xin
Chen, Hui
Abramson, Alex
Man, Huimin
Wu, Jinxia
Yu, Oliver
Nikolau, Basil
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© 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd
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Biochemistry, Biophysics and Molecular BiologyNSF Engineering Research Center for Biorenewable ChemicalsCenter for Metabolic Biology
Abstract
In this study we report the molecular genetic characterization of the Arabidopsis mitochondrial phosphopantetheinyl transferase (mtPPT), which catalyzes the phosphopantetheinylation and thus activation of mitochondrial acyl carrier protein (mtACP) of mitochondrial fatty acid synthase (mtFAS). This catalytic capability of the purified mtPPT protein (encoded by AT3G11470) was directly demonstrated in an in vitro assay that phosphopantetheinylated mature Arabidopsis apomtACP isoforms. The mitochondrial localization of the AT3G11470-encoded proteins was validated by the ability of their N-terminal 80-residue leader sequence to guide a chimeric GFP protein to this organelle. A T-DNA-tagged null mutant mtppt-1 allele shows an embryo-lethal phenotype, illustrating a crucial role of mtPPT for embryogenesis. Arabidopsis RNAi transgenic lines with reduced mtPPT expression display typical phenotypes associated with a deficiency in the mtFAS system, namely miniaturized plant morphology, slow growth, reduced lipoylation of mitochondrial proteins, and the hyperaccumulation of photorespiratory intermediates glycine and glycolate. These morphological and metabolic alterations are reversed when these plants are grown in a nonphotorespiratory condition (i.e., 1% CO2 atmosphere), demonstrating that they are a consequence of a deficiency in photorespiration due to the reduced lipoylation of the photorespiratory glycine decarboxylase.
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This is the peer reviewed version of the following article: Guan, Xin, Hui Chen, Alex Abramson, Huimin Man, Jinxia Wu, Oliver Yu, and Basil J. Nikolau. "A phosphopantetheinyl transferase that is essential for mitochondrial fatty acid biosynthesis." The Plant Journal 84, no. 4 (2015): 718-732, which has been published in final form at DOI:10.1111/tpj.13034. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.
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