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J Biol Chem. 2016 Oct 21;291(43):22793-22805. Epub 2016 Sep 2.

Ser/Thr Phosphorylation Regulates the Fatty Acyl-AMP Ligase Activity of FadD32, an Essential Enzyme in Mycolic Acid Biosynthesis.

Author information

1
From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS.
2
the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS UMR 5235, Place Eugène Bataillon, 34095 Montpellier Cedex 05, and.
3
the Institut Pasteur, Unité de Microbiologie Structurale, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France.
4
From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, mamadou.daffe@ipbs.fr.
5
From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, hedia.marrakchi@ipbs.fr.

Abstract

Mycolic acids are essential components of the mycobacterial cell envelope, and their biosynthetic pathway is a well known source of antituberculous drug targets. Among the promising new targets in the pathway, FadD32 is an essential enzyme required for the activation of the long meromycolic chain of mycolic acids and is essential for mycobacterial growth. Following the in-depth biochemical, biophysical, and structural characterization of FadD32, we investigated its putative regulation via post-translational modifications. Comparison of the fatty acyl-AMP ligase activity between phosphorylated and dephosphorylated FadD32 isoforms showed that the native protein is phosphorylated by serine/threonine protein kinases and that this phosphorylation induced a significant loss of activity. Mass spectrometry analysis of the native protein confirmed the post-translational modifications and identified Thr-552 as the phosphosite. Phosphoablative and phosphomimetic FadD32 mutant proteins confirmed both the position and the importance of the modification and its correlation with the negative regulation of FadD32 activity. Investigation of the mycolic acid condensation reaction catalyzed by Pks13, involving FadD32 as a partner, showed that FadD32 phosphorylation also impacts the condensation activity. Altogether, our results bring to light FadD32 phosphorylation by serine/threonine protein kinases and its correlation with the enzyme-negative regulation, thus shedding a new horizon on the mycolic acid biosynthesis modulation and possible inhibition strategies for this promising drug target.

KEYWORDS:

cell wall; lipid metabolism; mycobacteria; post-translational modification (PTM); protein phosphorylation

PMID:
27590338
PMCID:
PMC5077212
DOI:
10.1074/jbc.M116.748053
[Indexed for MEDLINE]
Free PMC Article

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