title: Role of Lipid Composition on the Interaction between a Tryptophan-Rich Protein and Model Bacterial Membranes.
abstract: The interaction between tryptophan-rich puroindoline proteins and model bacterial membranes at the air-liquid interface has been investigated by FTIR spectroscopy, surface pressure measurements, and Brewster angle microscopy. The role of different lipid constituents on the interactions between lipid membrane and protein was studied using wild type (Pin-b) and mutant (Trp44 to Arg44 mutant, Pin-bs) puroindoline proteins. The results show differences in the lipid selectivity of the two proteins in terms of preferential binding to specific lipid head groups in mixed lipid systems. Pin-b wild type was able to penetrate mixed layers of phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) head groups more deeply compared to the mutant Pin-bs. Increasing saturation of the lipid tails increased penetration and adsorption of Pin-b wild type, but again the response of the mutant form differed. The results provide insight as to the role of membrane architecture, lipid composition, and fluidity on antimicrobial activity of proteins. Data show distinct differences in the lipid binding behavior of Pin-b as a result of a single residue mutation, highlighting the importance of hydrophobic and charged amino acids in antimicrobial protein and peptide activity.
authors.affiliation: School of Pharmacy and Department of Food and Nutritional Sciences, University of Reading , PO Box 226, Whiteknights, Reading, Berkshire RG6 6AP, United Kingdom.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sanders
authors.affiliation: ISIS Pulsed Neutron and Muon Source, Science and technology Facilities Council, Rutherford Appleton Laboratory , Harwell Oxford Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom.
authors.forename: Luke A
authors.initials: LA
authors.lastname: Clifton
authors.affiliation: School of Pharmacy and Department of Food and Nutritional Sciences, University of Reading , PO Box 226, Whiteknights, Reading, Berkshire RG6 6AP, United Kingdom.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Frazier
authors.affiliation: School of Pharmacy and Department of Food and Nutritional Sciences, University of Reading , PO Box 226, Whiteknights, Reading, Berkshire RG6 6AP, United Kingdom.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Green
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D008567:Membranes, Artificial; D009154:Mutation; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D010715:Phosphatidylglycerols / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics; D017550:Spectroscopy, Fourier Transform Infrared; D014908:Triticum
chemical_list: D008563:Membrane Lipids; D008567:Membranes, Artificial; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; D010940:Plant Proteins; C082942:puroindoline protein, Triticum aestivum; C007510:1,2-dipalmitoyl-3-phosphatidylethanolamine; C030345:1,2-dipalmitoylphosphatidylglycerol