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Biochemical properties of staphylococcal (phospho)lipases
J W Simons1, F Götz, M R Egmond
1Department of Enzymology and Protein Engineering, Utrecht University, The Netherlands.
Chemistry and Physics of Lipids
|August 28, 1998
Summary
Staphylococcal lipases require calcium for stability, not activity. Molecular modeling and mutagenesis reveal key residues and a lid domain, suggesting calcium
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- Staphylococci secrete lipases crucial for various functions.
- Most staphylococcal lipases require calcium ions for activity and exhibit substrate chain length preferences.
- Staphylococcus hyicus lipase shows unique phospholipase activity.
Purpose of the Study:
- To provide an overview of the biochemical properties of staphylococcal lipases.
- To investigate the role of calcium ions and substrate chain length selectivity.
- To elucidate the structural and functional aspects of staphylococcal lipases using molecular modeling and mutagenesis.
Main Methods:
- Biochemical characterization of staphylococcal lipases.
- Molecular modeling based on X-ray structures of related lipases.
- Site-directed mutagenesis to verify calcium ligand identification.
Main Results:
- Substrate chain length selectivity is primarily determined by the acylation step, influenced by interfaces.
- Calcium ions stabilize staphylococcal lipases against denaturation but do not affect acylation/deacylation rates.
- Molecular modeling predicted key residues for substrate selectivity and identified a potential lid domain; mutagenesis confirmed a calcium-binding site.
Conclusions:
- Calcium ion-mediated stabilization of lipases may be a widespread phenomenon.
- Understanding staphylococcal lipase structure-function relationships is advanced by molecular modeling and mutagenesis.
- The study highlights the unique properties of Staphylococcus hyicus lipase and the general role of calcium in lipase stability.