With the rise in antibiotic resistance, antimicrobial peptides (AMPs) show promise for therapeutic development,. but higher specificity is required: PGLa-H is a naturally occurring decapeptide, repotted to have moderate antibacterial activity and low hemolytic activity; with its sequence being identical to that of the terminal fragment,,of highly selective AMP, PGLa. DiPGLa-H, a sequential tandem repeat of PGLa-H, and Kiadin, an analoglie with a Val to Gly substitution: at position 15, display improved in vitro bactericidal Activity against both Gram-negative and Gram-positive pathogens, with generally low toxicity for human cells. Despite Gly being a more flexible residue, NMR structural studies showed little difference in structure and dynamics between the two peptides for the first 14 residues, with somewhat greater flexibility in the C-terminus Kiadin resulting in a tighter structure of the peptide in the presence of sodium dodecyl sulfate micelles. AMPs found-organisms often exhibit minimal amino acid mutations, and such small differences in peptide conformation may be utilized to design more selective AMPs.