Biochemical characterization of a phospholipase A₂ homologue from the venom of the social wasp Polybia occidentalis

Rafaela Diniz-Sousa^1 2 3 4, Anderson M. Kayano^1 2, Cleópatra A. Caldeira^1 2 5, Rodrigo Simões-Silva^1 2, Marta C. Monteiro⁶, Leandro S. Moreira-Dill^1 2, Fernando P. Grabner^1 4, Leonardo A. Calderon^1 2, Juliana P. Zuliani^1 2, Rodrigo G. Stábeli^{1 7}, Andreimar M. Soares^1 2 4

 

1 Center for the Study of Biomolecules Applicable to Health (CEBio), Oswaldo Cruz Foundation – Rondônia (Fiocruz – Rondônia), Porto Velho, RO, Brazil.

2 Department of Medicine, Federal University of Rondônia (UNIR), Porto Velho, RO, Brazil.

3 Postgraduate Program in Experimental Biology (PGBIOEXP), Federal University of Rondônia (UNIR), Porto Velho, RO, Brazil.

4 São Lucas University Center (UniSL), Porto Velho, RO, Brazil.

5 Postgraduate Program in Biodiversity and Biotechnology, Bionorte Network, Federal University of Rondônia (UNIR), Porto Velho, RO, Brazil.

6 School of Pharmacy, Federal University of Pará (UFPA), Belém, PA, Brazil.

7 Department of Medicine, UFSCar, São Carlos, Center of Translational Medicine, Fiocruz – SP, and School of Medicine of Ribeirão Preto, University of São Paulo (USP), São Paulo, Brazil.

 

ABSTRACT

Background:

Wasp venoms constitute a molecular reservoir of new pharmacological substances such as peptides and proteins, biological property holders, many of which are yet to be identified. Exploring these sources may lead to the discovery of molecules hitherto unknown. This study describes, for the first time in hymenopteran venoms, the identification of an enzymatically inactive phospholipase A₂ (PLA₂) from the venom of the social wasp Polybia occidentalis.

Methods:

P. occidentalis venom was fractioned by molecular exclusion and reverse phase chromatography. For the biochemical characterization of the protein, 1D and 2D SDS-PAGE were performed, along with phospholipase activity assays on synthetic substrates, MALDI-TOF mass spectrometry and sequencing by Edman degradation.

Results:

The protein, called PocTX, was isolated using two chromatographic steps. Based on the phospholipase activity assay, electrophoresis and mass spectrometry, the protein presented a high degree of purity, with a mass of 13,896. 47 Da and a basic pI. After sequencing by the Edman degradation method, it was found that the protein showed a high identity with snake venom PLA₂ homologues.

Conclusion:

This is the first report of an enzymatically inactive PLA₂ isolated from wasp venom, similar to snake PLA₂homologues.

Keywords: Wasp; Polybia occidentalis; PocTX; PLA2 homologue

 

Received: June 28, 2017.

Accepted: January 19, 2018.

 

Correspondence: andreimarsoares@gmail.com

 

Authors’ contributions

RDS, AMK, CASC, RSS, LSMD biochemically and functionally characterized. RDS, AMK, CASC, RSS, LSMD, LAC, JPZ, RGS, AMS conducted all experiments, analyzed and discussed the results obtained. RDS, AMK, CASC, RSS, LSMD, FPG, LAC, JPZ, RGS, AMS participated in the analysis and discussion of the results, performed a critical revision of the work and assisted in the writing and structuring of the article. RDS, AMK, RGS, LAC, AMS was responsible for the design of the work, supervised all experiments and drafted the manuscript. All authors read and approved the final manuscript.

 

Competing interests

The authors declare that they have no competing interests.