Aggregation and Its Influence on the Bioactivities of a Novel Antimicrobial Peptide, Temporin-PF, and Its Analogues

Abstract

Temporin is an antimicrobial peptide (AMP) family discovered in the skin secretion of ranid frog that has become a promising alternative for conventional antibiotic therapy. Herein, a novel temporin peptide, Temporin-PF (TPF), was successfully identified from Pelophylax fukienensis. It exhibited potent activity against Gram-positive bacteria, but no effect on Gram-negative bacteria. Additionally, TPF exhibited aggregation effects in different solutions. Three analogs were further designed to study the relationship between the aggregation patterns and bioactivities, and the MD simulation was performed for revealing the pattern of the peptide assembly. As the results showed, all peptides were able to aggregate in the standard culture media and salt solutions, especially CaCl2 and MgCl2 buffers, where the aggregation was affected by the concentration of the salts. MD simulation reported that all peptides were able to form oligomers. The parent peptide assembly depended on the hydrophobic interaction via the residues in the middle domain of the sequence. However, the substitution of Trp/D-Trp resulted in an enhanced inter-peptide interaction in the zipper-like domain and eliminated overall biological activities. Our study suggested that introducing aromaticity at the zipper-like domain for temporin may not improve the bioactivities, which might be related to the formation of aggregates via the inter-peptide contacts at the zipper-like motif domain, and it could reduce the binding affinity to the lipid membrane of microorganisms.

Structure and Formation Mechanism of Antimicrobial Peptides Temporin B- and L-Induced Tubular Membrane Protrusion

“…However, at higher peptide concentration, TLs are more likely to associate into dimers, which on the contrary lowers their antibacterial activity as indicated by the reduced geometrical defect size (or larger k shown in Figure 9D) and rare membrane pore formation. Previous studies have shown that aggregation of AMPs may lower their potency to disrupt the membrane and reduce their antibacterial efficacy [60][61][62]. For example, Zai et al recently showed that removal of Phe residue at N-terminus and substitution of Trp/D-Trp at C-terminus of a novel temporin peptide, Temporin-PF (FLPLIAGLFGKIF), resulted in an enhanced inter-peptide interaction in the zipper-like domain and eliminated their overall biological activities [62].…”

“…Previous studies have shown that aggregation of AMPs may lower their potency to disrupt the membrane and reduce their antibacterial efficacy [60][61][62]. For example, Zai et al recently showed that removal of Phe residue at N-terminus and substitution of Trp/D-Trp at C-terminus of a novel temporin peptide, Temporin-PF (FLPLIAGLFGKIF), resulted in an enhanced inter-peptide interaction in the zipper-like domain and eliminated their overall biological activities [62]. This implies that hydrophobicity and aggregation level of AMPs must be balanced to achieve maximum antimicrobial efficacy.…”

SCMRSA: a New Approach for Identifying and Analyzing Anti-MRSA Peptides Using Estimated Propensity Scores of Dipeptides

“… 34 Likewise, temporin-PF identified from Pelophylax fukienensis displayed antimicrobial activity against MRSA (NCTC 12493), while it was ineffective against Gram-negative strains, such as Escherichia coli (NCTC 10418), P. aeruginosa (ATCC 27853), and K. pneumoniae (ATCC 43816), at a concentration of up to 128 μM. 36 However, Saha-CATH5 also exhibited a strong bactericidal activity against MRSA with a MIC of 32 μg/mL, while a concentration of 64 μg/mL had no effect against P. aeruginosa (ATCC 27853). 35 …”

“…Several studies mentioned that temporins were able to exhibit greater potencies against Gram-positive bacteria, such as S. aureus as compared to Gram-negative bacteria. ,, Moreover, temporin-SHd and Tasmanian devil cathelicidin Saha-CATH5 were ranked as the second and third potential anti-MRSA peptides, respectively. Temporin-SHd in the frog skin of Pelophylax saharicus was highly active against MRSA (ATCC 43300 and ATCC BAA-44) with a minimal inhibitory concentration (MIC) of 6.25 μM .…”

In Vitro & In Vivo Studies on Identifying and Designing Temporin-1CEh from the Skin Secretion of Rana chensinensis as the Optimised Antibacterial Prototype Drug

“…At the same time, the increase of hydrophobicity which resulted from the accumulation of a hydrophobic amino acid contributed to the aggregation between peptide molecules [ 54 , 55 ]. Too strong an aggregation ability may result in the premature aggregation of the peptide before they are attached to the cell membrane [ 56 , 57 , 58 ]. This can explain the decrease on the permeability and antibiofilm ability at high concentrations of T1CEh-KKPWW2 ( Figure 7 and Figure 8 ).…”