title: Structural insights for fatty acid binding in a Lys49-phospholipase A2: crystal structure of myotoxin II from Bothrops moojeni complexed with stearic acid.
abstract: The crystal structure of dimeric Lys49-phospholipase A2 myotoxin-II from Bothrops moojeni (MjTX-II) co-crystallized with stearic acid (C(18)H(36)O(2)) has been determined at a resolution of 1.8 A. The electron density maps permitted the unambiguous inclusion of six stearic acid molecules in the refinement. Two stearic acid molecules could be located in the substrate-binding cleft of each monomer in positions, which favor the interaction of their carboxyl groups with active site residues. The way of binding of stearic acids to this Lys49-PLA(2)s is analogous to phospholipids and transition state analogues to catalytically active PLA(2)s. Two additional stearic acid molecules were located at the dimer interface region, defining a hitherto unidentified acyl-binding site on the protein surface. The strictly conserved Lys122 for Lys49-PLA(2)s may play a fundamental role for stabilization of legend-protein complex. The comparison of MjTX-II/satiric acid complex with other Lys-PLA(2)s structures whose putative fatty acids were located at their active site is also analysed. Molecular details of the stearic acid/protein interactions provide insights to binding in group I/II PLA(2)s, and to the possible interactions of Lys49-PLA(2)s with target membranes.
authors.affiliation: Departamento de Física, IBILCE, UNESP, S. J. do Rio Preto-SP, Brazil.
authors.forename: Leandra
authors.initials: L
authors.lastname: Watanabe
authors.forename: Andreimar M
authors.initials: AM
authors.lastname: Soares
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Ward
authors.forename: Marcos R M
authors.initials: MR
authors.lastname: Fontes
authors.forename: Raghuvir K
authors.initials: RK
authors.lastname: Arni
mesh_terms: D000818:Animals; D001665:Binding Sites; D017837:Bothrops; D003435:Crotalid Venoms / Q000201:enzymology*; D018360:Crystallography, X-Ray; D054501:Group II Phospholipases A2; D010741:Phospholipases A / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D013229:Stearic Acids / Q000737:chemistry*
chemical_list: D003435:Crotalid Venoms; D013229:Stearic Acids; C031183:stearic acid; D010741:Phospholipases A; D054501:Group II Phospholipases A2