Design of new truncated derivatives based on direct and reverse mirror repeats of first six residues of Caerin 4 antimicrobial peptide and evaluation of their activity and cytotoxicity

Abstract

Caerin 4 is a family of AMPs isolated from the frog called Litoria caerulea. In silico drug designing methods and using machine learning algorithms for AMPs design can reduce their usage restrictions such as production costs and the time required for investigation of their activity and toxicity. In this study, two short peptides were designed based on direct and reverse mirror repeats of GLWQKI conserved sequence from Caerin 4 family that called dCar12 and rCar12. Also, Caerin 4.1 was synthesized without primary GLWQKI sequence and named Car7‐23. Following the synthesis of peptides, their antimicrobial properties, cytotoxicity, secondary structure, and mode of action were further evaluated. Results indicated that rCar12 had a good antibacterial activity (at an MIC of 3.9–62.5 µg/ml), while Car7‐23 did not have any antimicrobial properties. Cytotoxicity of rCar12 at MICs range was <5%, which is much less than Caerin 4.1. In conclusion, rCar12 with reverse mirror repeat has different functional properties compared with dCar12. These results corroborate the fact that in two peptides with identical residues and length, the position and arrangement of amino acids are very important concerning peptide function. Moreover, GLWQKI sequence is highly crucial for the antimicrobial activity of Caerin 4 antimicrobial peptide family.

Purification, and characterization of a new pro-coagulant protein from Iranian Echis carinatus venom

“…Subsequently, 150 μL of the supernatant was transferred to a new 96-well plate to measure the absorbance at 414 nm using a microplate reader (STAT FAX 2100, BioTek, Winooski, USA). The percentage of hemolysis was then calculated according to the provided formula [ 18 ]. …”

“…The measurements were conducted at a temperature of 25 °C, using a scanning speed of 200 nm/min and performing five scans. A 0.2–0.5 mg/mL of protein solution DDW was placed into a 1 mm quartz cell, and its spectra were scanned from 190 to 350 nm [ 18 ]. Subsequently, the data acquired from circular dichroism spectroscopy was analyzed to determine the proportionate ratio of secondary structural elements.…”

Synthesis and Synergistic Antimicrobial Efficacy of Covalent Conjugates Composed of Epsilon-Poly-l-lysine and Beta-Lactam Antibiotics

“…Nevertheless, their relatively high cytotoxicity, difficulties in production and purification, low proteolytic stability, and susceptibility to salt in physiological environments hinder their clinical utility . Hence, various strategies have been utilized to adapt AMPs, such as entrapping AMPs into carriers synthesized with polymers, liposomes, or lipids, − modifying their sequences by repeating, substituting or functionalizing, − and altering of the molecule structure by branching, linearization or cyclization . Additionally, strategies like conjugating AMPs with other functional molecules, such as siderophores and polylactic acid nanoparticles, are also feasible. , However, the high investment, limited outcome, and lengthy cost-recovery period associated with developing entirely new antimicrobial agents have discouraged pharmaceutical companies .…”