TY - JOUR
T1 - Limiting an antimicrobial peptide to the lipid-water interface enhances its bacterial membrane selectivity
T2 - A case study of MSI-367
AU - Thennarasu, Sathiah
AU - Huang, Rui
AU - Lee, Dong Kuk
AU - Yang, Pei
AU - Maloy, Lee
AU - Chen, Zhan
AU - Ramamoorthy, Ayyalusamy
PY - 2010/12/21
Y1 - 2010/12/21
N2 - In a minimalist design approach, a synthetic peptide MSI-367 [(KFAKKFA)3-NH2] was designed and synthesized with the objective of generating cell-selective nonlytic peptides, which have a significant bearing on cell targeting. The peptide exhibited potent activity against both bacteria and fungi, but no toxicity to human cells at micromolar concentrations. Bacterial versus human cell membrane selectivity of the peptide was determined via membrane permeabilization assays. Circular dichroism investigations revealed the intrinsic helix propensity of the peptide, β-turn structure in aqueous buffer and extended and turn conformations upon binding to lipid vesicles. Differential scanning calorimetry experiments with 1,2-dipalmitoleoyl-sn-glycero-3-phosphatidylethanolamine bilayers indicated the induction of positive curvature strain and repression of the fluid lamellar to inverted hexagonal phase transition by MSI-367. Results of isothermal titration calorimetry (ITC) experiments suggested the possibility of formation of specific lipid-peptide complexes leading to aggregation. 2H nuclear magnetic resonance (NMR) of deuterated 1-palmitoyl-2-oleoyl-sn-glycero-3- phosphatidylcholine (POPC) multilamellar vesicles confirmed the limited effect of the membrane-embedded peptide at the lipid-water interface. 31P NMR data indicated changes in the lipid headgroup orientation of POPC, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol, and 1-palmitoyl-2- oleoyl-sn-glycero-3-phosphatidylethanolamine lipid bilayers upon peptide binding. Membrane-embedded and membrane-inserted states of the peptide were observed via sum frequency generation vibrational spectroscopy. Circular dichroism, ITC, and 31P NMR data for Escherichia coli lipids agree with the hypothesis that strong electrostatic lipid-peptide interactions embrace the peptide at the lipid-water interface and provide the basis for bacterial cell selectivity.
AB - In a minimalist design approach, a synthetic peptide MSI-367 [(KFAKKFA)3-NH2] was designed and synthesized with the objective of generating cell-selective nonlytic peptides, which have a significant bearing on cell targeting. The peptide exhibited potent activity against both bacteria and fungi, but no toxicity to human cells at micromolar concentrations. Bacterial versus human cell membrane selectivity of the peptide was determined via membrane permeabilization assays. Circular dichroism investigations revealed the intrinsic helix propensity of the peptide, β-turn structure in aqueous buffer and extended and turn conformations upon binding to lipid vesicles. Differential scanning calorimetry experiments with 1,2-dipalmitoleoyl-sn-glycero-3-phosphatidylethanolamine bilayers indicated the induction of positive curvature strain and repression of the fluid lamellar to inverted hexagonal phase transition by MSI-367. Results of isothermal titration calorimetry (ITC) experiments suggested the possibility of formation of specific lipid-peptide complexes leading to aggregation. 2H nuclear magnetic resonance (NMR) of deuterated 1-palmitoyl-2-oleoyl-sn-glycero-3- phosphatidylcholine (POPC) multilamellar vesicles confirmed the limited effect of the membrane-embedded peptide at the lipid-water interface. 31P NMR data indicated changes in the lipid headgroup orientation of POPC, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol, and 1-palmitoyl-2- oleoyl-sn-glycero-3-phosphatidylethanolamine lipid bilayers upon peptide binding. Membrane-embedded and membrane-inserted states of the peptide were observed via sum frequency generation vibrational spectroscopy. Circular dichroism, ITC, and 31P NMR data for Escherichia coli lipids agree with the hypothesis that strong electrostatic lipid-peptide interactions embrace the peptide at the lipid-water interface and provide the basis for bacterial cell selectivity.
UR - https://www.scopus.com/pages/publications/78650348571
U2 - 10.1021/bi101394r
DO - 10.1021/bi101394r
M3 - Article
C2 - 21062093
AN - SCOPUS:78650348571
SN - 0006-2960
VL - 49
SP - 10595
EP - 10605
JO - Biochemistry
JF - Biochemistry
IS - 50
ER -