Design and Synthesis of N-terminal segment Peptides: A New Innovative Finding for Antimicrobial Activity

Abstract

Abstract A novel short N-terminal cationic and hydrophobic peptides, KWKLFKKI-CONH2 (P2) and KWLWKKI-CONH2 (P3) are a class of Cecropin-A family of KWKLFKKIQIAK-CONH2 (P1) was designed using Fmoc-chemistry solid phase peptide synthesis protocol, where W stands for α-(2,5,7-tri-tert-butylindol-3-yl) alanine residue. By comparing High performance liquid chromatograms or Mass spectrometry (LCMS or analytical HPLC), the purity, integrity, and homogeneity of the peptide were determined. The circular dichroism spectroscopy (CD) demonstrates that to detect conformational alterations during membrane contact, P2 adopts an extended structure in both polar and non-polar settings, as expected. Because of the presence of tryptophan derivatives, P3 occurs in an extended conformation. Peptide P2 exhibited an exceptional affinity for both zwitterionic POPC lipid bilayer and anionic POPC/POPG lipid bilayer membranes, whereas P3 preferentially interacts with POPC/POPG anionic bilayer rather than zwitterionic POPC lipid bilayer. Surprisingly, both peptides have good antibacterial activity against Gram-positive and Gram-negative microorganisms. It is important to note that the most hydrophobic P3 had more effectiveness against all test organisms than P2 and the control peptide P1. The toxicity of these peptides was examined using a hemolytic assay, and the results reveal that P2 and P3 have very little to no toxicity, which is important for P2 and P3 to be utilised as possible therapeutic agents. Peptides P2 and P3 were both non-hemolytic and appeared to be more capable due to their broad antibacterial activity.