Structure of an engineered porcine phospholipase A2 with enhanced activity at 2.1 A resolution. Comparison with the wild-type porcine and Crotalus atrox phospholipase A2.
The crystal structure of an engineered phospholipase A2 with enhanced activity has been refined to an R-factor of 18.6% at 2.1 A resolution using a combination of molecular dynamics refinement by the GROMOS package and least-squares refinement by TNT. This mutant phospholipase was obtained previously by deleting residues 62 to 66 in porcine pancreatic phospholipase A2, and changing Asp59 to Ser, Ser60 to Gly and Asn67 to Tyr. The refined structure allowed a detailed comparison with wild-type porcine and Crotalus atrox phospholipase A2. The conformation of the deletion region appears to be intermediate between that in those two enzymes. The residues in the active center are virtually the same. An internal hydrophobic area occupied by Phe63 in the wild-type porcine phospholipase A2 is kept as conserved as possible by local rearrangement of neighboring atoms. In the mutant structure, this hydrophobic pocket is now occupied by the disulfide bond between residues 61 and 91. A detailed description of the second binding site for a calcium ion in this enzyme is given.
Thunnissen
M M
MM
Laboratory of Chemical Physics, University of Groningen, The Netherlands.
Kalk
K H
KH
Drenth
J
J
Dijkstra
B W
BW
D000595:Amino Acid Sequence; D000818:Animals; D002872:Chromosome Deletion; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010741:Phospholipases A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054467:Phospholipases A2; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012911:Snakes; D012984:Software; D013552:Swine; D014961:X-Ray Diffraction
D011994:Recombinant Proteins; D010741:Phospholipases A; D054467:Phospholipases A2