Staphylococcus aureus adenosine triphosphatase: inhibitor sensitivity and release from membrane

Area of Science:

• Microbiology
• Biochemistry
• Enzymology

Background:

• Cytoplasmic membranes of Staphylococcus aureus harbor enzymatic activities crucial for cellular functions.
• Understanding membrane-associated enzymes like adenosine triphosphatase (ATPase) is vital for comprehending bacterial physiology.

Purpose of the Study:

• To characterize the membrane-associated adenosine triphosphatase (ATPase) activity in Staphylococcus aureus.
• To investigate the properties and modulators of this bacterial membrane ATPase.

Main Methods:

• Isolation of homogeneous cytoplasmic membrane preparations from Staphylococcus aureus.
• Assay of ATPase activity under varying conditions (divalent cations, pH, substrates).
• Solubilization of the enzyme using detergents (Triton X-100, SDS) and characterization via polyacrylamide gel electrophoresis.
• Assessment of inhibition and activation by various chemical agents (N,N'-dicyclohexylcarbodiimide, NaF, azide, trypsin, ouabain, diethylstilbestrol).

Main Results:

• Membrane-associated ATPase activity was observed, with optimal activity at pH 6.5.
• Activity was activated by divalent cations, with Mg2+ showing the highest effect, and preferred ATP hydrolysis.
• The enzyme was detergent-solubilized, and its electrophoretic behavior differed slightly depending on the detergent used.
• Specific inhibitors (N,N'-dicyclohexylcarbodiimide, NaF, azide, trypsin) and an activator (diethylstilbestrol) were identified.

Conclusions:

• Staphylococcus aureus possesses a distinct membrane-associated ATPase enzyme.
• The enzyme's characteristics, including cation dependency, pH optimum, and susceptibility to inhibitors/activators, provide insights into its function.
• Detergent-based solubilization and electrophoretic analysis offer methods for further purification and characterization of this important bacterial enzyme.