title: Another example of enzymatic promiscuity: the polyphosphate kinase of Streptomyces lividans is endowed with phospholipase D activity.
abstract: Polyphosphate kinases (PPK) from different bacteria, including that of Streptomyces lividans, were shown to contain the typical HKD motif present in phospholipase D (PLD) and showed structural similarities to the latter. This observation prompted us to investigate the PLD activity of PPK of S. lividans, in vitro. The ability of PPK to catalyze the hydrolysis of phosphatidylcholine (PC), the PLD substrate, was assessed by the quantification of [3H]phosphatidic acid (PA) released from [3H]PC-labeled ELT3 cell membranes. Basal cell membrane PLD activity as well as GTPγS-activated PLD activity was higher in the presence than in absence of PPK. After abolition of the basal PLD activity of the membranes by heat or tryptic treatment, the addition of PPK to cell membranes was still accompanied by an increased production of PA demonstrating that PPK also bears a PLD activity. PLD activity of PPK was also assessed by the production of choline from hydrolysis of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in the presence of the Amplex Red reagent and compared to two commercial PLD enzymes. These data demonstrated that PPK is endowed with a weak but clearly detectable PLD activity. The question of the biological signification, if any, of this enzymatic promiscuity is discussed.
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), Group "Energetic Metabolism of Streptomyces", CEA, CNRS, University of Paris-Sud, INRA, University Paris-Saclay, F-91198, Gif-sur-Yvette Cedex, France.|Sorbonne Universities, UPMC University of Paris 06, UFR 927, Sciences de la vie, F-75005, Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Esnault
authors.affiliation: INSERM U1063, University of Angers, IBS-IRIS Rue des Capucins, F-49100, Angers, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Leiber
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), Group "RNA Sequence, Structure & Function", CEA, CNRS, University of Paris-Sud, INRA, University Paris-Saclay, F-91198, Gif-sur-Yvette Cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Toffano-Nioche
authors.affiliation: Institut de Biologie Animale, Intégrative et Cellulaire (IBAIC), INSERM U1174, University of Paris-Sud, 91405, Orsay Cedex, France.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Tanfin
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), Group "Energetic Metabolism of Streptomyces", CEA, CNRS, University of Paris-Sud, INRA, University Paris-Saclay, F-91198, Gif-sur-Yvette Cedex, France. marie-joelle.virolle@i2bc.paris-saclay.fr.
authors.forename: Marie-Joelle
authors.initials: MJ
authors.lastname: Virolle
mesh_terms: D020816:Amino Acid Motifs; D002462:Cell Membrane / Q000201:enzymology; D002794:Choline / Q000378:metabolism; D006868:Hydrolysis; D010712:Phosphatidic Acids / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism; D010739:Phospholipase D / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D048170:Streptomyces lividans / Q000201:enzymology* / Q000235:genetics
chemical_list: D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D017856:Phosphotransferases (Phosphate Group Acceptor); C022424:polyphosphate kinase; D010739:Phospholipase D; C017251:1,2-oleoylphosphatidylcholine; D002794:Choline
keywords: Lipid droplets; Phospholipase D; Polyphosphate kinase; Promiscuous enzyme