title: Effect of acyl chain length on therapeutic activity and mode of action of the CX-KYR-NH2 antimicrobial lipopeptide.
abstract: Peptide lipidation has proven to be an inexpensive and effective strategy for designing next-generation peptide-based drug compounds. In this study, the effect of the acyl chain length of ultrashort LiPs (CX-KYR-NH2; X=10, 12, 14 and 16) on their bacterial killing and membrane disruption kinetics was investigated. The geometric mean of the minimum inhibitory concentration (MIC) values for 4 pathogenic bacterial strains was 25 μM, with a selectivity index of 10.24 for C14-KYR-NH2. LiPs at all concentrations exhibited no cytotoxicity towards human erythrocytes, but towards Vero cells at 80 μM. All the LiPs adopted secondary structure in a membrane mimicking environment. C14-KYR-NH2 aggregated above 256 μM, while C16-KYR-NH2 did above 80 μM. All LiPs showed outer membrane permeabilization within 3 min after treatment, yet the extent and kinetics of inner membrane penetration and depolarization were dependent on the acyl chain length. Cell death subsequently occurred within 10 min, and killing activity appeared to correlate most with depolarization activity but not with outer or inner membrane permeability. AFM imaging of cells treated with C14-KYR-NH2 revealed rupture of the cell surface and cytosolic leakage depending on the length of incubation. This study highlights and follows the progression of events that occur during the membrane disintegration process over time, and determines the optimal amphipathicity of ultrashort LiPs with 12-14 carbon atoms for this membrane disrupting activity. The fast acting bactericidal properties of ultrashort LiPs with optimal chain lengths make them promising candidates for drug lead compounds.
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; Protein and Proteomics Research Center for Commercial and Industrial Purposes, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Sawinee
authors.initials: S
authors.lastname: Nasompag
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; Protein and Proteomics Research Center for Commercial and Industrial Purposes, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Punpimon
authors.initials: P
authors.lastname: Dechsiri
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; Protein and Proteomics Research Center for Commercial and Industrial Purposes, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Nuttaya
authors.initials: N
authors.lastname: Hongsing
authors.affiliation: Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Prasart
authors.initials: P
authors.lastname: Phonimdaeng
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; Protein and Proteomics Research Center for Commercial and Industrial Purposes, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Sakda
authors.initials: S
authors.lastname: Daduang
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; Protein and Proteomics Research Center for Commercial and Industrial Purposes, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Sompong
authors.initials: S
authors.lastname: Klaynongsruang
authors.affiliation: Department of Chemical Engineering, Worcester Polytechnic Institute, MA 01609, USA.
authors.forename: Terri A
authors.initials: TA
authors.lastname: Camesano
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; Protein and Proteomics Research Center for Commercial and Industrial Purposes, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Rina
authors.initials: R
authors.lastname: Patramanon
mesh_terms: D000215:Acylation; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis* / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D018407:Bacterial Physiological Phenomena / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D015195:Drug Design; D055666:Lipopeptides / Q000138:chemical synthesis* / Q000494:pharmacology*; D008970:Molecular Weight; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D055666:Lipopeptides
keywords: Acyl chain; Antimicrobial; Atomic force microscope; Lipopeptide; Membrane permeabilization; Mode of action