title: Utilization of an amphipathic leucine zipper sequence to design antibacterial peptides with simultaneous modulation of toxic activity against human red blood cells.
abstract: The toxicity of naturally occurring or designed antimicrobial peptides is a major barrier for converting them into drugs. To synthesize antimicrobial peptides with reduced toxicity, several amphipathic peptides were designed based on the leucine zipper sequence. The first one was a leucine zipper peptide (LZP); in others, leucine residues at the a- and/or d-position were substituted with single or double alanine residues. The results showed that LZP and its analogs exhibited appreciable and similar antibacterial activity against the tested gram-positive and gram-negative bacteria. However, the substitution of alanine progressively lowered the toxicity of LZP against human red blood cells (hRBCs). The substitution of leucine with alanine impaired the binding and localization of LZP to hRBCs, but had little effect on the peptide-induced damage of Escherichia coli cells. Although LZP and its analogs exhibited similar permeability, secondary structures, and localization in negatively charged membranes, significant differences were observed among these peptides in zwitterionic membranes. The results suggest a novel approach for designing antibacterial peptides with modulation of toxicity against hRBCs by employing the leucine zipper sequence. Also, to the best of our knowledge, the results demonstrate that this sequence could be utilized to design novel cell-selective molecules for the first time.
authors.affiliation: Molecular and Structural Biology Division, University of Oxford, Oxford OX3 7LD, United Kingdom.
authors.forename: Aqeel
authors.initials: A
authors.lastname: Ahmad
authors.affiliation: Molecular and Structural Biology Division, University of Oxford, Oxford OX3 7LD, United Kingdom.
authors.forename: Sharada Prasad
authors.initials: SP
authors.lastname: Yadav
authors.affiliation: Molecular and Structural Biology Division, University of Oxford, Oxford OX3 7LD, United Kingdom.
authors.forename: Neeta
authors.initials: N
authors.lastname: Asthana
authors.affiliation: Electron Microscopy Unit, Central Drug Research Institute, Lucknow 226 001, India.
authors.forename: Kalyan
authors.initials: K
authors.lastname: Mitra
authors.affiliation: Molecular and Structural Biology Division, University of Oxford, Oxford OX3 7LD, United Kingdom.
authors.forename: Swati Prakash
authors.initials: SP
authors.lastname: Srivastava
authors.affiliation: Molecular and Structural Biology Division, University of Oxford, Oxford OX3 7LD, United Kingdom. Electronic address: jighosh@yahoo.com.
authors.forename: Jimut Kanti
authors.initials: JK
authors.lastname: Ghosh
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D002463:Cell Membrane Permeability / Q000187:drug effects; D015195:Drug Design; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects*; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D016350:Leucine Zippers; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D009842:Oligopeptides