title: IR spectroscopy analysis of pancreatic lipase-related protein 2 interaction with phospholipids: 1. Discriminative recognition of mixed micelles versus liposomes.
abstract: Guinea pig pancreatic lipase-related protein 2 (GPLRP2) is an interesting model enzyme that can hydrolyze a large set of acylglycerols in vitro but displays however some selectivity depending on the supramolecular structure of substrate and the presence of surfactants like bile salts. We showed that GPLRP2 hydrolyzes 1,2-dipalmitoyl phosphatidylcholine (DPPC) present in mixed micelles with sodium taurodeoxycholate (NaTDC) but not in multilamellar (MLV) and large unilamellar (LUV) vesicles of DPPC. After characterization of these lipid aggregates by dynamic light scattering (DLS), the discriminative recognition of DPPC in DPPC/NaTDC micelles versus MLV and LUV by an inactive variant (S152G) of GPLRP2 to avoid the effect of substrate hydrolysis was investigated using Fourier transform infrared spectroscopy (FTIR). IR spectra were recorded after hydrogen/deuterium exchange, at pD 6 and various temperatures to study phase transitions. We analyzed the methylene asymmetric stretching (ν(CH2)as), the carbonyl stretching (ν(CO)) and the composite polar head-group vibration bands, first to characterized differences in DPPC micelles and vesicles, and second to estimate the degree of interaction of GPLRP2 S152G with phospholipid. Our results indicate that a significant interaction between GPLRP2 S152G and DPPC is only observed when NaTDC is added to the system to form micelles and this can be explained by the different organization of DPPC in mixed micelles compared to lamellar vesicles (higher hydration of polar head, higher mobility of alkyl chains) that favors GPLRP2 penetration into the phospholipid layer.
authors.affiliation: CNRS, Aix-Marseille Université, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Mateos-Diaz
authors.affiliation: CNRS, Aix-Marseille Université, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Bakala N'Goma
authors.affiliation: CNRS, Aix-Marseille Université, FR3479 Institut de Microbiologie de la Méditerranée, Marseille, France.
authors.forename: Deborah
authors.initials: D
authors.lastname: Byrne
authors.affiliation: CNRS, Aix-Marseille Université, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Robert
authors.affiliation: CNRS, Aix-Marseille Université, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France. Electronic address: carriere@imm.cnrs.fr.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Carrière
authors.affiliation: CNRS, Aix-Marseille Université, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France. Electronic address: Helene.Gaussier@imm.cnrs.fr.
authors.forename: Hélène
authors.initials: H
authors.lastname: Gaussier
mesh_terms: D000818:Animals; D006168:Guinea Pigs; D006868:Hydrolysis; D008049:Lipase / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D008066:Lipolysis; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008823:Micelles; D010179:Pancreas / Q000201:enzymology*; D010743:Phospholipids / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D013055:Spectrophotometry, Infrared
chemical_list: D008081:Liposomes; D008823:Micelles; D010743:Phospholipids; D008049:Lipase; C075988:pancreatic lipase related protein 2
keywords: Enzyme; FTIR spectroscopy; Lipid digestion; Lipids; Lipolysis; Phospholipase