Preparation of an antimicrobial surface by direct assembly of antimicrobial peptide with its surface binding activity

2017 ◽  
Vol 5 (13) ◽  
pp. 2407-2415 ◽  
Author(s):  
Junjian Chen ◽  
Yuchen Zhu ◽  
Yancheng Song ◽  
Lin Wang ◽  
Jiezhao Zhan ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Polymethyl Methacrylate ◽  
Binding Activity ◽  
Surface Binding ◽  
Direct Assembly

The designed antimicrobial peptide has surface binding activity onto titanium, gold, polymethyl methacrylate and hydroxyapatite substrates.

scholarly journals Functional Characterization of a Novel Promoter Element Required for an Innate Immune Response in Drosophila

2003 ◽  
Vol 23 (22) ◽  
pp. 8272-8281 ◽  
Author(s):  
Hanna Uvell ◽  
Ylva Engström
Keyword(s):  
Gene Expression ◽  
Antimicrobial Peptide ◽  
Functional Characterization ◽  
Binding Activity ◽  
Innate Immune ◽  
Site Directed Mutagenesis ◽  
Promoter Element ◽  
Peptide Gene ◽  
Inducible Genes

ABSTRACT Innate immune reactions are crucial processes of metazoans to protect the organism against overgrowth of faster replicating microorganisms. Drosophila melanogaster is a precious model for genetic and molecular studies of the innate immune system. In response to infection, the concerted action of a battery of antimicrobial peptides ensures efficient killing of the microbes. The induced gene expression relies on translocation of the Drosophila Rel transcription factors Relish, Dif, and Dorsal to the nucleus where they bind to κB-like motifs in the promoters of the inducible genes. We have identified another putative promoter element, called region 1 (R1), in a number of antimicrobial peptide genes. Site-directed mutagenesis of the R1 site diminished Cecropin A1 (CecA1) expression in transgenic Drosophila larvae and flies. Infection of flies induced a nuclear R1-binding activity that was unrelated to the κB-binding activity in the same extracts. Although the R1 motif was required for Rel protein-mediated CecA1 expression in cotransfection experiments, our data argue against it being a direct target for the Drosophila Rel proteins. We propose that the R1 and κB motifs are targets for distinct regulatory complexes that act in concert to promote high levels of antimicrobial peptide gene expression in response to infection.

The ovine pancreatic protein which binds insulin-like growth factor binding protein-3 is procarboxypeptidase A

1996 ◽  
Vol 150 (1) ◽  
pp. 51-56 ◽  
Author(s):  
P J Fowke ◽  
S C Hodgkinson
Keyword(s):  
Growth Factor ◽  
Cell Surface ◽  
Binding Protein ◽  
Binding Activity ◽  
Insulin Like Growth Factor ◽  
Surface Binding ◽  
Factor Binding ◽  
Amino Terminal ◽  
Igf I ◽  
Igfbp 3

Abstract Insulin-like growth factor binding protein-3 (IGFBP-3) is known to modulate the actions of insulin-like growth factors (IGF)-I and -II at the level of the cell. Proposed mechanisms include association of IGFBP-3 with cell surface proteoglycan, with cell surface binding proteins, proteolysis and/or internalization of IGFBP-3. In previous studies we have characterized a protein of 40 kDa in extracts of ovine pancreas and muscle which binds IGFBP-3 on ligand blot analyses. This paper reports the identity of the pancreatic species as procarboxypeptidase A (peptidyl-l-amino acid hydrolase, E.C. 3.4.17.1; proCPA). Identity was established by amino terminal sequence analysis, binding studies with pure bovine carboxypeptidase A (CPA) and observations that the binding activity was present in pancreatic secretions consistent with the role of proCPA as a secretory zymogen. The binding activity was inhibited by unlabelled IGFBP-3 at high doses (10 μg/ml) and reduced but not abolished by preincubation of 125I-IGFBP-3 with excess IGF-I. Digestion of 125I-IGFBP-3 with mature CPA produced a 26 kDa product. Modification of IGFBP-3 by CPA or binding to proCPA may provide a mechanism for modulation of IGFBP activity and hence IGF action. Journal of Endocrinology (1996) 150, 51–56

scholarly journals Interactions of the designed antimicrobial peptide MB21 and truncated dermaseptin S3 with lipid bilayers: molecular-dynamics simulations

2003 ◽  
Vol 370 (1) ◽  
pp. 233-243 ◽  
Author(s):  
Craig M. SHEPHERD ◽  
Hans J. VOGEL ◽  
D. Peter TIELEMAN
Keyword(s):  
Molecular Dynamics ◽  
Antimicrobial Peptide ◽  
Molecular Dynamics Simulations ◽  
Lipid Bilayers ◽  
Helical Conformation ◽  
Constraint Forces ◽  
Surface Binding ◽  
Lipid Interactions ◽  
Area Per Lipid ◽  
Dynamics Simulations

Molecular-dynamics simulations covering 30ns of both a natural and a synthetic antimicrobial peptide in the presence of a zwitterionic lipid bilayer were performed. In both simulations, copies of the peptides were placed in an α-helical conformation on either side of the bilayer about 10Å (1Å = 0.1nm) from the interface, with either the hydrophobic or the positively charged face of the helix directed toward the bilayer surface. The degree of peptide—lipid interaction was dependent on the starting configuration: surface binding and subsequent penetration of the bilayer was observed for the hydrophobically oriented peptides, while the charge-oriented peptides demonstrated at most partial surface binding. Aromatic residues near the N-termini of the peptides appear to play an important role in driving peptide—lipid interactions. A correlation between the extent of peptide—lipid interactions and helical stability was observed in the simulations. Insertion of the peptides into the bilayer caused a dramatic increase in the lateral area per lipid and decrease in the bilayer thickness, resulting in substantial disordering of the lipid chains. Results from the simulations are consistent with early stages of proposed mechanisms for the lytic activity of antimicrobial peptides. In addition to these ‘free’ simulations, 25ns simulations were carried out with the peptides constrained at three different distances relative to the bilayer interface. The constraint forces are in agreement with the extent of peptide—bilayer insertion observed in the free simulations.

scholarly journals Monensin inhibits recycling of macrophage mannose-glycoprotein receptors and ligand delivery to lysosomes

1984 ◽  
Vol 220 (3) ◽  
pp. 665-675 ◽  
Author(s):  
T Wileman ◽  
R L Boshans ◽  
P Schlesinger ◽  
P Stahl
Keyword(s):  
Cell Surface ◽  
Specific Binding ◽  
Binding Activity ◽  
Surface Binding ◽  
Binding Studies ◽  
Receptor Ligand ◽  
Lysosomal Fraction ◽  
Cell Surface Binding ◽  
Monensin A ◽  
Proton Movement

Binding studies with cells that had been permeabilized with saponin indicate that alveolar macrophages have an intracellular pool of mannose-specific binding sites which is about 4-fold greater than the cell surface pool. Monensin, a carboxylic ionophore which mediates proton movement across membranes, has no effect on binding of ligand to macrophages but blocks receptor-mediated uptake of 125I-labelled beta-glucuronidase. Inhibition of uptake was concentration- and time-dependent. Internalization of receptor-bound ligand, after warming to 37 degrees C, was unaffected by monensin. Moreover, internalization of ligand in the presence of monensin resulted in an intracellular accumulation of receptor-ligand complexes. The monensin effect was not dependent on the presence of ligand, since incubation of macrophages with monensin at 37 degrees C without ligand resulted in a substantial decrease in cell-surface binding activity. However, total binding activity, measured in the presence of saponin, was much less affected by monensin treatment. Removal of monensin followed by a brief incubation at pH 6.0 and 37 degrees C, restored both cell-surface binding and uptake activity. Fractionation experiments indicate that ligands enter a low-density (endosomal) fraction within the first few minutes of uptake, and within 20 min transfer to the lysosomal fraction has occurred. Monensin blocks the transfer from endosomal to lysosomal fraction. Lysosomal pH, as measured by the fluorescein-dextran method, was increased by monensin in the same concentration range that blocked ligand uptake. The results indicate that monensin blockade of receptor-mediated endocytosis of mannose-terminated ligands by macrophages is due to entrapment of receptor-ligand complexes and probably receptors in the pre-lysosomal compartment. The inhibition is linked with an increase in the pH of acid intracellular vesicles.

scholarly journals Influence of Acyl Chain Saturation on the Membrane-Binding Activity of a Short Antimicrobial Peptide

ACS Omega ◽  
2017 ◽  
Vol 2 (11) ◽  
pp. 7482-7492 ◽  
Author(s):  
Daniela Ciumac ◽  
Richard A. Campbell ◽  
Luke A. Clifton ◽  
Hai Xu ◽  
Giovanna Fragneto ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Acyl Chain ◽  
Membrane Binding ◽  
Binding Activity

Abstract 5: ApoAI Binds to Phosphatidylinositol 4,5 Bisphosphate (PIP2), Which is Exposed on the Cell Surface by Novel PIP2 Floppase Activity of ABCA1, and Promotes Cholesterol Efflux

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Kailash Gulshan ◽  
Gregory Brubaker ◽  
Stanley Hazen ◽  
Jonathan Smith
Keyword(s):  
Cell Surface ◽  
Cholesterol Efflux ◽  
Binding Activity ◽  
Mouse Bone Marrow ◽  
Dependent Manner ◽  
Ph Domain ◽  
Surface Binding ◽  
Raw264.7 Macrophages ◽  
Lipid Species ◽  
Phosphatidylinositol Phosphates

Introduction: ApoAI-ABCA1 mediated nascent HDL assembly promotes cholesterol efflux and reverse cholesterol transport, but the mechanism of HDL assembly is unknown. Objective: To determine role of PIP2 in ApoAI-ABCA1 mediated nascent HDL assembly. Methods and Results: To determine which lipid species are directly bound by apoAI, a lipid-protein overlay assay was performed using PIPstrips and sphingostrips from Echelon Biosciences. ApoAI bound directly to phosphatidylinositol phosphates (PIPs) rather than PC, PS, PE, SM or cholesterol. This interaction was not solely electrostatic, as PIP3, the most negative charged PIP had less apoAI binding than various PIP2 species. ApoAI did not bind to other charged lipids such as sphingosine 1-P, PI(3)-P, PI(4)-P, and PI(5)-P. Surface plasmon resonance assays using immobilized apoAI or PIP2 were performed, showing that apoAI interacted reversibly with PI(4,5)P2 in a dose dependent manner at the nM concentration range. The central domain of apoAI (residues 44-185) was sufficient for PIP2 binding. In RAW264.7 macrophages, depletion of cellular PIPs by treatments with PI3K inhibitor or PTEN inhibitor decreased cholesterol efflux by 45±1.4% and 41±6.4% respectively (p<0.005). Degradation of cell surface PIP2 via treatment with PI specific PLC decreased cell surface binding of apoAI by 37±6% and cholesterol efflux by 48±8% (p<0.005). In mouse bone-marrow derived macrophages, cholesterol efflux to apoAI was increased ~47% by GRIP (PIP2 binding PH domain of PLCδ) and decreased 41±8% by PTEN inhibition (p<0.005). Liposomes made with POPC:POPS:FC:PIP2 (65:20:10:5 mole ratio) were solubilized by apoAI at 37 o C, pH5, but apoAI had little activity using similar liposomes without PIP2 . ABCA1 expression led to 2-fold higher cell surface PIP2, assayed by flow cytometry using a PIP2 specific antibody. RAW cells stably transfected with PIP2 binding domain 2X PH-PLCδ-eGFP showed enrichment of this PIP2 reporter on the plasma membrane, while expression of ABCA1 led to partial redistribution to cytoplasm, consistent with ABCA1 having PIP2 floppase activity. Conclusions: ApoAI has novel PIP2 binding activity, ABCA1 is a novel PIP2 floppase, and cell surface PIP2 is required for optimal cholesterol acceptor activity of apoAI.

Cytolocalization artifacts with immunofluorescent probes

1986 ◽  
Vol 64 (12) ◽  
pp. 1326-1332 ◽  
Author(s):  
Susan J. Friedman ◽  
Catharine L. Dewar ◽  
Philip Skehan
Keyword(s):  
Immunofluorescence Microscopy ◽  
Lectin Binding ◽  
Active Form ◽  
Binding Activity ◽  
Insoluble Residue ◽  
Surface Binding ◽  
Intact Cells ◽  
Nonionic Detergent ◽  
Choriocarcinoma Cells ◽  
Membrane Components

Formaldehyde fixation, nonionic detergent extraction, and ligand binding are commonly used in conjunction with immunofluorescence microscopy to visualize antigens and lectin-reactive molecules in cytoskeletal preparations. These procedures have the potential to produce serious artifacts in cytolocalization studies, as is shown in the present investigation of wheat-germ agglutinin (WGA) binding and localization in BeWo choriocarcinoma cells. Formaldehyde fixation of intact cells reduced the binding of 125I-labeled WGA by 30% and altered the pattern of staining with fluorescein isothyocyanate (FITC)–WGA. Except for perinuclear sites which were brightly stained, the binding of FITC–WGA to other cell surface regions was significantly decreased. Nonionic detergent extractions had two different effects on lectin binding activity depending on whether or not the cells had been pretreated with lectin. In lectin-pretreated cells, 50% of bound lectin was solubilized by detergent but all of the surface binding sites appeared to be retained in active form in the detergent-insoluble residue. Nuclear-cytoskeletal monolayers prepared from cells that were not lectin pretreated lost considerable binding activity, however. These results suggest that a number of erroneous conclusions can be drawn from studies on cytoskeletal associations with membrane components using immunofluorescence microscopy on fixed and detergent-extracted cells.

scholarly journals CENP-B box is required for de novo centromere chromatin assembly on human alphoid DNA

2002 ◽  
Vol 159 (5) ◽  
pp. 765-775 ◽  
Author(s):  
Jun-ichirou Ohzeki ◽  
Megumi Nakano ◽  
Teruaki Okada ◽  
Hiroshi Masumoto
Keyword(s):  
Dna Sequence ◽  
Dna Sequences ◽  
De Novo ◽  
Repetitive Sequences ◽  
Point Mutations ◽  
Artificial Chromosome ◽  
Binding Activity ◽  
Chromatin Assembly ◽  
Direct Assembly ◽  
Alphoid Dna

Centromere protein (CENP) B boxes, recognition sequences of CENP-B, appear at regular intervals in human centromeric α-satellite DNA (alphoid DNA). In this study, to determine whether information carried by the primary sequence of alphoid DNA is involved in assembly of functional human centromeres, we created four kinds of synthetic repetitive sequences: modified alphoid DNA with point mutations in all CENP-B boxes, resulting in loss of all CENP-B binding activity; unmodified alphoid DNA containing functional CENP-B boxes; and nonalphoid repetitive DNA sequences with or without functional CENP-B boxes. These four synthetic repetitive DNAs were introduced into cultured human cells (HT1080), and de novo centromere assembly was assessed using the mammalian artificial chromosome (MAC) formation assay. We found that both the CENP-B box and the alphoid DNA sequence are required for de novo MAC formation and assembly of functional centromere components such as CENP-A, CENP-C, and CENP-E. Using the chromatin immunoprecipitation assay, we found that direct assembly of CENP-A and CENP-B in cells with synthetic alphoid DNA required functional CENP-B boxes. To the best of our knowledge, this is the first reported evidence of a functional molecular link between a centromere-specific DNA sequence and centromeric chromatin assembly in humans.

Sign in / Sign up

Export Citation Format

Share Document