Honeybee Venom Phospholipase A2 Research Articles

Illustrating Interfacial Interaction between Honey Bee Venom Phospholipase A2 and Supported Negatively Charged Lipids with Sum Frequency Generation and Laser Scanning Confocal Microscopy.

Phospholipase A2 is an important enzyme species which can widely be found in animals, plants, bacteria, and so on. A large number of studies have shown that phospholipase A2 is highly catalytic toward the lipids. Here, sum frequency generation (SFG) vibrational spectroscopy and laser scanning confocal microscopy (LSCM) were applied to study the interaction between honey bee venom phospholipase A2 (bvPLA2) and the negatively charged DPPG bilayer. In both cases without and with the calcium ions (Ca2+), the bvPLA2 molecules were adsorbed onto the outer leaflet surface with the orientational order, and the adsorbed bvPLA2 molecules damaged the order of the packed outer leaflet. In comparison to the case without Ca2+, the addition of Ca2+ can accelerate the attaching process of bvPLA2 to the outer leaflet surface and decelerate the process of damaging the outer leaflet order. The experimental result also confirmed, with the help of the Ca2+, the DPPG molecules in the outer leaflet were hydrolyzed, with both hydrolysates, that is, lysophospholipids and fatty acids, remaining at the interface, showing a distinct difference from previous published literatures regarding neutral lipids [Phys. Chem. Chem. Phys. 2018, 20, 63-67] and PLA1 [Langmuir 2019, 35, 12831-12838].

Calcium-dependent hydrolysis of supported planar lipids was triggered by honey bee venom phospholipase A2 with the right orientation at the interface.

Hydrolysis of planar phospholipids catalyzed by honey bee venom phospholipase A2 (bvPLA2) was studied. Experiments demonstrated that Ca2+ ions mediated between the lipids and bvPLA2, induced reorientation of bvPLA2, and activated hydrolysis. One of the hydrolysis products, fatty acids, was desorbed, and the other one, lysophospholipids, self-organized at the interface.

Simultaneous Determination of Absolute Configuration and Quantity of Lipopeptides Using Chiral Liquid Chromatography/Mass Spectrometry and Diastereomeric Internal Standards.

Lipopeptides promote innate immune response and are related to disease pathology. To investigate the newly emerging roles of lipopeptides, accurate measurements of stereoisomers with multiple chiral centers are essential yet challenging. This work uses (3R)- and (3S)-(15-methyl-3-((13-methyltetradecanoyl)oxy)hexadecanoyl)glycyl-l-serine, abbreviated as l-serine-(R+S)-Lipid 654, to develop a method that combines chiral liquid chromatography, a diastereomeric mixture of isotopically labeled internal standards, and multiple reaction monitoring mass spectrometry. The new method allows for simultaneously determining the absolute configuration and quantity of stereoisomers of bacteria-derived lipopeptides. Total lipid extracts of nine evaluated bacteria strains had different amounts, but only the (R)-isoform of l-serine-Lipid 654. The developed method also allowed for the first quantitative analysis of hydrolysis of a nonphospholipid as a novel substrate of honey bee venom phospholipase A2.

A Question of Nature: Some Antigens are Bound to be Allergens.

A Question of Nature: Some Antigens are Bound to be Allergens.

Role of carbohydrate moieties in IgE binding to allergenic components of Cupressus arizonica pollen extract.

A reduction of IgE immunoreactivity after periodate-treatment has been previously reported for various glycoprotein allergens. The aim of this study was to investigate the role of glycan moiety of a C. arizonica extract in the binding of patients' IgE and to identify the carbohydrates possibly involved. The reactivity of IgE with C. arizonica extract, before and after periodate-treatment, was evaluated by immunoblotting and ELISA inhibition. The specificity of carbohydrate-reactive IgE was evaluated by ELISA using unrelated glycoproteins with known sugar composition and structure, such as pineapple bromelain, honeybee venom phospholipase A2, and ovalbumin, before and after periodate treatment. When periodate-treated C. arizonica extract was probed after SDS-PAGE and immunoblotting with patients' IgE, no reactivity could be detected. Furthermore, a very poor inhibitory activity of the periodate-treated C. arizonica extract as compared with the untreated sample could be observed in the ELISA inhibition experiments performed using C. arizonica extract as antigen. When phospholipase A2 and bromelain were used as antigens in ELISA, they were recognized by patients' IgE, whereas ovalbumin was negative. Treatment of phospholipase A2 and bromelain with periodate completely abolishes the IgE reactivity. A large portion of the IgE reactivity of Cupressaceae-allergic subjects appears to be associated with sugar moieties of C. arizonica extract which appear to be shared by bromelain and phospholipase A2, thus suggesting that the IgE of patients reacting with such epitopes probably react with beta 1 --> 2 xylose, alpha 1 --> 3 fucose and/or alpha 1 --> 6 fucose.

Cross-reactivity between the major allergen from olive pollen and unrelated glycoproteins: Evidence of an epitope in the glycan moiety of the allergen

Ole e 1, the major allergen from olive pollen, is a glycoprotein containing a single Asn-linked glycan moiety. Rabbit antiserum against this protein has been obtained; and its immunologic cross-reactivities in Western blotting with ascorbate oxidase, horseradish peroxidase, bromelain, ovalbumin, and honeybee venom phospholipase A2 have been studied. Ascorbate oxidase, peroxidase, and bromelain are recognized by the Ole e 1 antiserum. When these three proteins are deglycosylated by periodate treatment, such an immunologic reaction does not occur. The relative affinities of these proteins have been analyzed by direct and inhibition ELISA experiments. A commercially available antibody against horseradish peroxidase has also been considered in these studies. This antibody reacts with Ole e 1 but not with the periodate-deglycosylated allergen. Horseradish peroxidase, bromelain, and ascorbate oxidase are recognized by the IgE of sera from patients who are hypersensitive to olive tree pollen. This binding is also abolished by periodate treatment. The results are interpreted in terms of the presence of an epitope in the carbohydrate moiety of Ole e 1, which would contain a xylose involved in recognition by both IgE and IgG antibodies. (J ALLERGY CLIN IMMUNOL 1996;97:1264-71.)

Immunotherapy with T-cell-reactive peptides derived from allergens.

Immunotherapy with T-cell-reactive peptides derived from allergens.

Primary structures of the N-linked carbohydrate chains from honeybee venom phospholipase A2.

The N-linked carbohydrate chains of phospholipase A2 from honeybee (Apis mellifera) were released from glycopeptides with peptide-N-glycanase A and reductively aminated with 2-aminopyridine. The fluorescent derivatives were separated by size-fractionation and reverse-phase HPLC, yielding 14 fractions. Structural analysis was accomplished by compositional and methylation analyses, by comparison of the HPLC elution patterns with reference oligosaccharides, by stepwise exoglycosidase digestions which were monitored by HPLC, and, where necessary, by 500-MHz 1H-NMR spectroscopy. Ten oligosaccharides consisted of mannose, N-acetylglucosamine and fucose alpha 1-6 and/or alpha 1-3 linked to the innermost N-acetylglucosamine. Four compounds, which comprised 10% of the oligosaccharide pool from phospholipase A2, contained a rarely found terminal element with N-acetylgalactosamine. The structures of the 14 N-glycans from honeybee phospholipase A2 can be arranged into the following three series: [formula: see text]

Alpha 1-6(alpha 1-3)-difucosylation of the asparagine-bound N-acetylglucosamine in honeybee venom phospholipase A2.

Chymotryptic glycopeptides were prepared from a honeybee (Apis mellifica) venom phospholipase A2 (E.C. 3.1.1.4) fraction, with high affinity towards lentil (Lens culinaris) lectin. Treatment of the glycopeptide mixture with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase A, followed by HPLC fractionation, yielded two oligosaccharides, which were analysed by 500 MHz 1H-NMR spectroscopy to give the following structures [formula: see text] This is the first report on a naturally occurring glycoprotein N-glycan with two fucose residues linked to the asparagine-bound N-acetylglucosamine.

Regulation of the immune response to allergens by immunosuppressive allergenic fragments. 1. Peptic fragments of honey bee venom phospholipase A2.

Nine patients with anaphylactic sensitivity to honey bee venom (HBV) were treated with P-1, a pepsin derived fragment of HBV phospholipase A2 (PLA2). P-1 caused only rare reactions with doses of 100 micrograms/injection. Treatment resulted in a substantial decrease in specific anti-PLA2 IgE and IgG antibodies as well as a decline in skin test sensitivity to PLA2. Another group of HBV-sensitive patients was treated with unaltered PLA2. Doses greater than 20 micrograms/injection were not tolerated. PLA2 injections caused an increase in anti-PLA2 IgG and IgE antibodies as well as increase in skin test sensitivity. This study demonstrates that a nonimmunogenic fragment derived from an allergen can downregulate immune responses and thus offer a new modality for therapy of allergic diseases.