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Stabilization vs. degradation of Staphylococcus aureus metalloproteinase
J Potempa1, Z Porwit-Bobr, J Travis
1Department of Microbiology and Immunology, Jagiellonian University, Kraków, Poland.
Biochimica Et Biophysica Acta
|December 8, 1989
Summary
A contaminating serine proteinase degrades Staphylococcus aureus metalloproteinase when EDTA is present. Adding calcium or removing the serine proteinase prevents this degradation, clarifying metalloproteinase stability.
Area of Science:
- Microbiology
- Enzymology
- Protein Chemistry
Background:
- Staphylococcus aureus metalloproteinase (Stp) is an important virulence factor.
- Previous studies suggested Stp is resistant to autolysis.
- Trace serine proteinase contamination in purified Stp preparations was noted.
Purpose of the Study:
- To investigate the cause of apparent autolysis of purified Staphylococcus aureus metalloproteinase.
- To elucidate the role of metal ions and contaminating serine proteinase in Stp degradation.
Main Methods:
- Purification of Staphylococcus aureus metalloproteinase.
- Enzymatic assays with and without EDTA, Ca2+, or Zn2+.
- Immunoaffinity chromatography to remove serine proteinase.
- Treatment with o-phenanthroline to chelate Zn2+.
Main Results:
- EDTA induced rapid degradation of Stp by a contaminating serine proteinase.
- Addition of Ca2+ or removal of the serine proteinase prevented degradation.
- Chelation of Zn2+ by o-phenanthroline did not cause degradation of the metal-free apometalloproteinase.
- EDTA's action involves irreversible inactivation and conformational changes facilitating proteolysis.
Conclusions:
- The apparent autolysis of purified Stp is due to degradation by a contaminating serine proteinase.
- EDTA-induced metal chelation causes conformational changes leading to serine proteinase susceptibility.
- This finding explains discrepancies in previous reports on Stp stability.