Structural basis of the myotoxic inhibition of the Bothrops pirajai PrTX-I by the synthetic varespladib.
Salvador, G.H.M., Pinto, E.K.R., Ortolani, P.L., Fortes-Dias, C.L., Cavalcante, W.L.G., Soares, A.M., Lomonte, B., Lewin, M.R., Fontes, M.R.M.(2023) Biochimie 207: 1-10
- PubMed: 36403756 
- DOI: https://doi.org/10.1016/j.biochi.2022.11.006
- Primary Citation of Related Structures:  
8DND - PubMed Abstract: 
Varespladib (LY315920) is a potent inhibitor of human group IIA phospholipase A 2 (PLA 2 ) originally developed to control inflammatory cascades of diseases associated with high or dysregulated levels of endogenous PLA 2 . Recently, varespladib was also found to inhibit snake venom PLA 2 and PLA 2 -like toxins. Herein, ex vivo neuromuscular blocking activity assays were used to test the inhibitory activity of varespladib. The binding affinity between varespladib and a PLA 2 -like toxin was quantified and compared with other potential inhibitors for this class of proteins. Crystallographic and bioinformatic studies showed that varespladib binds to PrTX-I and BthTX-I into their hydrophobic channels, similarly to other previously characterized PLA 2 -like myotoxins. However, a new finding is that an additional varespladib binds to the MDiS region, a particular site that is related to muscle cell disruption by these toxins. The present results further advance the characterization of the molecular interactions of varespladib with PLA 2 -like myotoxins and provide additional evidence for this compound as a promising inhibitor candidate for different PLA 2 and PLA 2 -like toxins.
Organizational Affiliation: 
Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, Brazil.