Revision as of 21:20, 21 October 2021

Tachyplesin-I

Tachyplesin I (TP-I) is a cysteine-rich antimicrobial peptide derived from the hemocytes of horseshoe crabs. It is very similar in structure, sequence, and function to Protegrin-1, containing the same disulfide bridges and resulting beta-sheet secondary structure which allows it to form pores in the membrane. This antimicrobial peptide was the first gene that we designed. Similar to how St. Andrews created BBa_K117000, the gene sequence for TP-I was derived by translating the amino acid residues to their most common codon triplet, putting those triplets in order, and adding start and stop codons.

Further research into the action of tachyplesin and protegrin revealed that in addition to having antimicrobial ability, both peptides also exhibited some degree of hemolytic activity against human erythrocytes. In the interest of safety, we wanted to find a way to get rid of the hemolytic activity without abolishing the antimicrobial action. Some more digging led us to research that had been done on versions of both of these antimicrobial peptides in which all cysteine residues had been removed. For tachyplesin, it was found that while the deletion of cysteines somewhat decreased the peptides antibiotic capacity, it completely got rid of its ability to lyse human red blood cells. Likewise, the deletion of cysteines in protegrin was found to have little effect on its ability to kill bacteria, however there was no investigation into its hemolytic activity. Based on this information, we decided to develop genes for these cysteine-deleted antimicrobial peptides and investigate them further.

Sequence and Features

2020 SZPT-CHIAN

Characterization

As a broad-spectrum antimicrobial peptide, TP-1 has good inhibitory effect on most microorganisms. This year, our project use TP-1 as the antibacterial module of Streptococcus mutans. The following is the results of our Bacteriostatic Experiment. As shown in following, the MIC value of TP-1 against Streptococcus mutans is 8 μg/mL, indicating that TP-1 has a good inhibitory effect on Streptococcus mutans.

2021 HKIS

HKIS Improvement

A AI model machine learning has been ran to improve the cytotoxicity of the peptide and generated several mutant candidates.