Thanatin is an inducible 21-residue cationic antimicrobial peptide that was first isolated from the hemolymph of the hemipteran insect Podisus maculiventris (spined soldier bug), through immune challenge. Thanatin is strongly cationic (pI of 10.48) and contains a distinct short eight-residue basic loop created through a disulfide bond formation between residues Cys11 and Cys18 at the C-terminus. Thanatin exerts bactericidal activity by disrupting outer membrane(OM) integrity. Thanatin damages the OM by promoting the release of divalent cations. Thanatin competitively replaces the divalent cations to bind to LPS, thereby disrupting the integrity of OM and leading to bacterial death.
Ma, B., Fang, C., Lu, L. et al. The antimicrobial peptide thanatin disrupts the bacterial outer membrane and inactivates the NDM-1 metallo-β-lactamase. Nat Commun 10, 3517 (2019).
Dash R, Bhattacharjya S. Thanatin: An Emerging Host Defense Antimicrobial Peptide with Multiple Modes of Action. Int J Mol Sci. 2021 Feb 3;22(4):1522. doi: 10.3390/ijms22041522. PMID: 33546369; PMCID: PMC7913509.