NMR STRUCTURES OF A COMPUTATIONALLY DESIGNED PEPTIDES DERIVED FROM Cry10Aa TOXIN

According to the World Health Organization (WHO), diseases resulting from Antimicrobial Resistance (AMR) already cause at least 700,000 deaths per year worldwide [1]. In this perspective, antimicrobial peptides (AMPs) have emerged as strong candidates to replace conventional drugs, which are no longer sufficiently effective.

The Cry10Aa toxin has been identified as a protein source for generating a new antimicrobials peptide, as this toxin has shown effective results in combating insect pests and controlling bovine mastitis. In this regard, the α-helix 3 of the Cry10Aa toxin was used as a template in the Joker algorithm for generating new antimicrobial peptides. Six new variants were generated, and their biological activities were evaluated, along with the original peptide AMPCry10Aa. Among the new variants, the AMPCry10Aa_5 peptide demonstrated the best results in terms of minimum inhibitory concentration against gram-positive and gram-negative bacteria. AMPCry10Aa (IINVLTSIVTPIKNQLDKYQ-NH2) is a peptide composed of 20 amino acid residues cut from the α-helix 3 of the Cry10Aa toxin. AMPCry10Aa_5 (IINVKTSLKTIIKNALDKIQ-NH2) is a synthetic peptide consisting of 20 amino acid residues derived from the sequence of the parental peptide, AMPCry10Aa.

In this sense, both AMPCry10Aa and AMPCry10Aa_5 peptides had their three-dimensional structures determined by 2D NMR due to their recognition as promising antimicrobial drugs. The AMPCry10Aa and AMPCry10Aa_5 peptides revealed an α-helical folding between residues Ile2-Gln20 and Val4-Ile19, respectively. The structural results showed good convergence of the obtained low-energy structures, evidenced by the low RMSD values of 0.4641 ± 0.1467 and 0.1393 ± 0.0467 for AMPCry10Aa and AMPCry10Aa_5, respectively. Finally, the determination of the peptides’ three-dimensional structures through NMR provided a better understanding of their mechanism of action, allowing the association of structural and dynamic characteristics of the molecule with its biological function.

1.WHO. Global Priority List of Antibiotic-Resistant-Bacteria to Guide Research, Discovery and Development of NewAntibiotics, 2017.

Acknowledgments: CAPES;CNPq;FAPEG;and PPGQ-IQ/UFG.