title: Kinetic and structural characterization of triacylglycerol lipases possessing phospholipase A1 activity.
abstract: The pancreatic lipase gene family displays various substrate selectivities for triglycerides and phospholipids. The structural basis for this difference in substrate specificity has not been definitively established. Based on a kinetic comparative study between various pancreatic lipase family members, we showed here that porcine pancreatic lipase (PPL), which was so far classified as "classical lipase", was able to hydrolyze phosphatidylcholine (PC). Amino acid sequence alignments revealed that Val260 residue in PPL lid could be critical for the interaction with lipid substrate. Molecular dynamics was applied to investigate PC binding modes within the catalytic cavity of PPL and human pancreatic lipase (HPL), aiming to explain the difference of specificity of these enzymes towards phospholipids. Results showed that with HPL, the oxyanion hole was not able to accommodate the PC molecule, suggesting that no activity could be obtained. With PPL, the formation of a large pocket involving Val260 allowed the PC molecule to come near the catalytic residues, suggesting that it could be hydrolyzed. One more interesting finding is that human pancreatic lipase related protein 2 could hydrolyze phospholipids through its PLA1 and PLA2 activities. Overall, our study shed the light on new structural features of the phospholipase activity of pancreatic lipase family members.
authors.affiliation: University of Sfax, ENIS, Laboratory of Biochemistry and Enzymatic Engineering of Lipases, 3038 Sfax, Tunisia. Electronic address: aloulou@u.washington.edu.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Aloulou
authors.affiliation: University of Sfax, ENIS, Laboratory of Biochemistry and Enzymatic Engineering of Lipases, 3038 Sfax, Tunisia.
authors.forename: Fakher
authors.initials: F
authors.lastname: Frikha
authors.affiliation: CNRS Université Claude Bernard Lyon 1, ICBMS, Organization and Dynamics of Biological Membranes, UMR 5246, Bâtiment Raulin, 43, Boulevard du 11 Novembre 1918, 69622 Villeurbanne, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Noiriel
authors.affiliation: University of Sfax, ENIS, Laboratory of Biochemistry and Enzymatic Engineering of Lipases, 3038 Sfax, Tunisia.
authors.forename: Madiha
authors.initials: M
authors.lastname: Bou Ali
authors.affiliation: CNRS Université Claude Bernard Lyon 1, ICBMS, Organization and Dynamics of Biological Membranes, UMR 5246, Bâtiment Raulin, 43, Boulevard du 11 Novembre 1918, 69622 Villeurbanne, France. Electronic address: abousalham@univ-lyon1.fr.
authors.forename: Abdelkarim
authors.initials: A
authors.lastname: Abousalham
mesh_terms: D000818:Animals; D006801:Humans; D007700:Kinetics; D008049:Lipase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism; D054466:Phospholipases A1 / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D054467:Phospholipases A2 / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D020539:Sequence Analysis, Protein; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013552:Swine
chemical_list: D010713:Phosphatidylcholines; D008049:Lipase; C518354:PNLIP protein, human; D054466:Phospholipases A1; D054467:Phospholipases A2
keywords: Activity; Human pancreatic lipase; Human pancreatic lipase related protein 2; Phospholipase A(1); Porcine pancreatic lipase; Regioselectivity