title: Atomic resolution (0.97 A) structure of the triple mutant (K53,56,121M) of bovine pancreatic phospholipase A2.
abstract: The enzyme phospholipase A2 catalyzes the hydrolysis of the sn-2 acyl chain of phospholipids, forming fatty acids and lysophospholipids. The crystal structure of a triple mutant (K53,56,121M) of bovine pancreatic phospholipase A2 in which the lysine residues at positions 53, 56 and 121 are replaced recombinantly by methionines has been determined at atomic resolution (0.97 A). The crystal is monoclinic (space group P2), with unit-cell parameters a = 36.934, b = 23.863, c = 65.931 A, beta = 101.47 degrees. The structure was solved by molecular replacement and has been refined to a final R factor of 10.6% (Rfree = 13.4%) using 63,926 unique reflections. The final protein model consists of 123 amino-acid residues, two calcium ions, one chloride ion, 243 water molecules and six 2-methyl-2,4-pentanediol molecules. The surface-loop residues 60-70 are ordered and have clear electron density.
authors.affiliation: Bioinformatics Centre, Indian Institute of Science, Bangalore 560 012, India. sekar@physics.iisc.ernet.in
authors.forename: K
authors.initials: K
authors.lastname: Sekar
authors.forename: V
authors.initials: V
authors.lastname: Rajakannan
authors.forename: D
authors.initials: D
authors.lastname: Gayathri
authors.forename: D
authors.initials: D
authors.lastname: Velmurugan
authors.forename: M-J
authors.initials: MJ
authors.lastname: Poi
authors.forename: M
authors.initials: M
authors.lastname: Dauter
authors.forename: Z
authors.initials: Z
authors.lastname: Dauter
authors.forename: M-D
authors.initials: MD
authors.lastname: Tsai
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D018360:Crystallography, X-Ray; D017931:DNA Primers; D005612:Freeze Drying; D006860:Hydrogen Bonding; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010179:Pancreas / Q000201:enzymology*; D010741:Phospholipases A / Q000737:chemistry* / Q000235:genetics; D054467:Phospholipases A2; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D017931:DNA Primers; D011994:Recombinant Proteins; D010741:Phospholipases A; D054467:Phospholipases A2