AUTHOR=Ramirez Merlano Juan Antonio , Almeida Daniela Volcan 

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

JOURNAL=Frontiers in Genetics

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2022.812971

DOI=10.3389/fgene.2022.812971

ISSN=1664-8021

ABSTRACT=<p>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 piranha <italic>Pygocentrus nattereri</italic> and to evaluate its effect on bacterial growth. The gene that encodes cystatin-B was isolated from the spleen of <italic>P. nattereri</italic> and cloned in an expression system. The protein was produced via a heterologous system involving the yeast <italic>Pichia pastoris</italic> X-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 the <italic>Kirby-Bauer</italic> method on the growth of <italic>Escherichia coli</italic> and <italic>Bacillus subtilis</italic>. rCYST-B showed 100% inhibition at a concentration of 60 μg/μL. Moreover, the bacteriostatic activity of <italic>E. coli</italic> and <italic>B. subtilis</italic> showed 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.</p>