Structure of porcine pancreatic phospholipase A2 at 2·6resolution and comparison with bovine phospholipase A2
| Autor: | Bauke W. Dijkstra, Roland Renetseder, Kor H. Kalk, Wim G.J. Hol, Jan Drenth, R. Huber |
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| Rok vydání: | 1983 |
| Předmět: |
Protein Conformation
Swine Stereochemistry Peptide Phospholipase Phospholipases A Phospholipase A2 Structural Biology Animals Molecular replacement Amino Acid Sequence Pancreas Molecular Biology chemistry.chemical_classification Enzyme Precursors Phospholipase A Binding Sites Crystallography biology Active site Amino acid Phospholipases A2 Enzyme chemistry Phospholipases biology.protein Calcium Cattle |
| Zdroj: | Journal of Molecular Biology, 168(1), 163-179. Academic Press |
| ISSN: | 0022-2836 |
| Popis: | The previously published three-dimensional structure of porcine pancreatic prophospholipase A 2 at 3resolution was found to be incompatible with the structures of bovine phospholipase A 2 and bovine prophospholipase A 2 . This was unexpected because of the very homologous amino acid sequences of these enzymes. Therefore, the crystal structure of the porcine enzyme was redetermined using molecular replacement methods with bovine phospholipase as the parent model. The structure was crystallographically refined at 2·6resolution by fast Fourier transform and restrained least-squares procedures to an R -factor of 0·241. The crystals appeared to contain phospholipase A 2 and not prophospholipase A 2 . Apparently the protein is slowly converted under the crystallization conditions employed. Our investigation shows that, in contrast to the previous report, the three-dimensional structure of porcine phospholipase A 2 is very similar to that of bovine phospholipase A 2 , including the active site. Smaller differences were observed in some residues involved in the binding of aggregated substrates. However, an appreciable conformational difference is in the loop 59 to 70, where a single substitution at position 63 (bovine Val→porcine Phe) causes a complete rearrangement of the peptide chain. In addition to the calcium ion in the active site, a second calcium ion is present in the crystals; this is located on a crystallographic 2-fold axis and stabilizes the interaction between two neighbouring molecules. |
| Databáze: | OpenAIRE |
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