Heterologous Production and Evaluation of the Biological Activity of Cystatin-B From the Red Piranha Pygocentrus nattereri

Abstract

Cystatin proteins are known to form a superfamily of cysteine protease inhibitors, which play a key role in protein degradation and are related to different physiological processes, such as development and immunity. Currently, numerous immunoregulatory proteins, such as cystatins, are being used in the control and prevention of diseases in aquaculture. Thus, the objective of this study was to produce recombinant cystatin (rCYST-B) from the red piranhaPygocentrus nattereriand to evaluate its effect on bacterial growth. The gene that encodes cystatin-B was isolated from the spleen ofP. nattereriand cloned in an expression system. The protein was produced via a heterologous system involving the yeastPichia pastorisX-33. The inhibitory activity of purified cystatin-B was evaluated on papain using different concentrations (0–80.0 μg/μL) of rCYST-B. The bacteriostatic action of the protein was evaluated using theKirby-Bauermethod on the growth ofEscherichia coliandBacillus subtilis. rCYST-B showed 100% inhibition at a concentration of 60 μg/μL. Moreover, the bacteriostatic activity ofE. coliandB. subtilisshowed inhibition of 40.36 and 49.08% compared to the negative control (phosphate buffer), respectively. These results suggest that recombinant CYST-B has biotechnological potential for use in aquaculture.