Aquaculture 2022

February 28 - March 4, 2022

San Diego, California

INTERACTION STUDIES OF THE B SUBUNIT OF PIRABvp TOXIN FROM Vibrio parahaemolyticus WITH THEIR RECEPTORS: IN SILICO AND EXPERIMENTAL APPROACH

Marcelo Victorio-De Los Santos1*, Ma. de Jesús Durán-Avelar1, Edgar Zenteno2, Georgina Garza2, Norberto Vibanco-Pérez1. Miriam Fabiola Ayón-Perez, Alejandro Vazquez-Reyes

 

1Autonomous University of Nayarit, Research Laboratory in Molecular Biology and Immunology, Cd. de la Cultura, CEMIC 05 building, Tepic, Nayarit, 63190, México.

2National Autonomous University of Mexico, Department of Biochemistry, School of Medicine, Cd. Universitaria, 2nd floor “D” building,  CDMX, 04510, México.

mvictorio@uan.edu.mx

 



The main virulence factor of the Acute hepatopancreatic necrosis disease (AHPND) in  Penaeus vannamei shrimp is the binary toxin PirABvp ,  secreted by Vibrio parahaemolyticus, which causes massive sloughing  of epithelial cells from the tubules of the hepatopancreas.  There are reports that the PirBvp  subunit possesses lectin activity recognizing amino sugars .  Also, h as been reported that this damage it’s through recognition of a specific sugars sequence of the glycoprotein s on epithelial cells hepatopancreas.  To explore possible  sugar  specific  linked and  effects, we performed  in silico analysis and  comparative structural studies on the rPirAvp and rPirBvp subunits and the tetrameric complex of PirABvp purified by affinity chromatography to galactose-sepharose 4B .  Analysis of rPirAvp and rPirBvp subunits by circular dichroism, dynamic light scattering , fluorescence-based thermal shift assays and extrinsic fluorescence , in the absence of octylglucoside, showed highly disordered structures that tend to aggregate. However, w hen octyl glucoside was used as a ligand to both subunits,  was observed that only the PirBvp coupled to the ligand and was structurally stable, this was not observed with the PirAvp subunit. When ligand-galactose binding assays were performed for the native tetrameric PirABvp complex, an increase in the thermostability of the complex was observed.  This data suggest that its necessary a sugar, like galactose, for thermostability of pirABvp complex, and the octylgalactoside for structural stability of  the  rPirBvp subunit, which suggests that the carbohydrate recognition site is in the B subunit .