In silico encrypted peptide from green alga Tetraspora sp. CU2551 showed high antimicrobial activities

Abstract

The green alga Tetraspora sp. CU2551 has been previously identified as a biohydrogen producer for an alternative option for sustainable energy production development. Its biomass still contains a source of valuable biomolecules, especially proteins. Crude algal protein showed significant antimicrobial activity against Gram-positive bacteria (Bacillus subtilis TISTR 1248 and Staphylococcus aureus TISTR 746) and Gram-negative bacteria (Escherichia coli TISTR 074 and Pseudomonas aeruginosa TISTR 2370), representing a clear zone of 19.0 ± 0.1, 18.3 ± 0.5, 17.7 ± 0.5, and 19.0 ± 0.5, respectively. Further investigation revealed that encrypted peptides from pepsin-hydrolyzed crude proteins increased the inhibition activity against these bacteria by 3.4–10.5 %. The hydrolyzed peptides were fractionated using a Sephadex G-25 column, and peptides in fraction 17 showed the highest antimicrobial activity. Through peptide identification using LC-MS and prediction of obtained peptide primary sequences with four bioinformatic tools (DBAASP, AMPDiscover, iAMPpred, and AMPscanner), five peptides were selected and synthesized for activity evaluation. The PT11 peptide (RYGAAMAVGIACA) demonstrated the highest antimicrobial activity among the five peptides tested and compared favorably to previously reported algal encrypted peptides. The findings of this research demonstrate that the encrypted PT11 peptide derived from Tetraspora sp. CU2551 has promising potential as an antimicrobial agent. Additionally, we suggest that PT11 might be used for other things besides this, like animal feed.