Functional interaction between Cerebratulus lacteus cytolysin A-III and phospholipase A/sub 2/

Journal Article · Sun May 15 00:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:6771999

Liu, J; Blumenthal, K M

A study on the interaction between bee venom phospholipase A/sub 2/ and Cerebratulus lacteus cytolysin A-III, a major hemolysin secreted by this organism has been carried out. The hemolytic activity of A-III in phosphate-buffered saline is increased 5-fold in the presence of phospholipase A/sub 2/ from bee venom. Dansylphosphatidylethanolamine (DPE) labeled, phosphatidylcholine-containing liposomes and human erythrocyte membranes were employed to study the interaction between these two proteins. In DPE-liposomes, A-III alone had no effect on DPE fluorescence nor did it enhance either the phospholipase A/sub 2/-dependent fluorescence increase or blue shift in emission maximum, indicating that the cytolysis is not a major phospholipase A/sub 2/-activator. However, when DPE was incorporated into erythrocyte membranes, A-III alone induced a 40% fluorescence increase and a 5 nm blue shift, implying a transient activation of an endogenous phospholipase A/sub 2/. Further studies using synthetic lysophosphatidylcholine and free fatty acids demonstrated that the hemolytic activity of A-III is potentiated by free fatty acids, a product of phospholipid degradation catalyzed by phospholipase A/sub 2/. Subsequent analysis of this phenomenon by gel filtration chromatography, analytical ultracentrifugation, chemical cross-linking, and measurement of (/sup 14/C)oleic acid binding by the cytolysin demonstrated that binding of oleic acid to A-III causes aggregation of the toxin molecules to a tetrameric form which has a higher ..cap alpha..-helix content and a greater activity than the monomer.

• Research Organization: Univ. of Cincinnati College of Medicine, OH (USA)
• OSTI ID: 6771999
• Journal Information: J. Biol. Chem.; (United States), Vol. 263:14
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CARBON 14 COMPOUNDS
TRACER TECHNIQUES
LIPASE
CONFIGURATION INTERACTION
PROTEINS
FLUORESCENCE
HEMOLYSIS
OLEIC ACID
CARBOXYLESTERASES
CARBOXYLIC ACIDS
ENZYMES
ESTERASES
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LUMINESCENCE
LYSIS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PATHOLOGICAL CHANGES
550201* - Biochemistry- Tracer Techniques