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  • 1.
    Boesze-Battaglia, Kathleen
    et al.
    University of Penn, PA 19104 USA.
    Walker, Lisa P.
    University of Penn, PA 19104 USA.
    Zekavat, Ali
    University of Penn, PA 19104 USA.
    Dlakic, Mensur
    Montana State University, MT 59717 USA.
    Damek Scuron, Monika
    University of Penn, PA 19104 USA.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Shenker, Bruce J.
    University of Penn, PA 19104 USA.
    The Aggregatibacter actinomycetemcomitans Cytolethal Distending Toxin Active Subunit CdtB Contains a Cholesterol Recognition Sequence Required for Toxin Binding and Subunit Internalization2015In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 83, no 10, p. 4042-4055Article in journal (Refereed)
    Abstract [en]

    Induction of cell cycle arrest in lymphocytes following exposure to the Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) is dependent upon the integrity of lipid membrane microdomains. Moreover, we have previously demonstrated that the association of Cdt with target cells involves the CdtC subunit which binds to cholesterol via a cholesterol recognition amino acid consensus sequence (CRAC site). In this study, we demonstrate that the active Cdt subunit, CdtB, also is capable of binding to large unilamellar vesicles (LUVs) containing cholesterol. Furthermore, CdtB binding to cholesterol involves a similar CRAC site as that demonstrated for CdtC. Mutation of the CRAC site reduces binding to model membranes as well as toxin binding and CdtB internalization in both Jurkat cells and human macrophages. A concomitant reduction in Cdt-induced toxicity was also noted, indicated by reduced cell cycle arrest and apoptosis in Jurkat cells and a reduction in the proinflammatory response in macrophages (interleukin 1 beta [IL-1 beta] and tumor necrosis factor alpha [TNF-alpha] release). Collectively, these observations indicate that membrane cholesterol serves as an essential ligand for both CdtC and CdtB and, further, that this binding is necessary for both internalization of CdtB and subsequent molecular events leading to intoxication of cells.

  • 2.
    Ederth, Thomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Ekblad, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Östblom, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Pettitt, M.E.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Callow, M.E.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Callow, J.A.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Interactions of algal spores and diatoms with mixed synthetic peptide SAMs2007Conference paper (Other academic)
  • 3.
    Ederth, Thomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Pettitt, M. E.
    University of Birmingham.
    Oumlstblom, M.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Du, Chun-Xia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Broo, Klas
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Callow, M. E.
    University of Birmingham.
    Callow, J.
    University of Birmingham.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Anomalous settlement behavior of Ulva linza zoospores on cationic oligopeptide surfaces2008In: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 24, no 4, p. 303-312Article in journal (Refereed)
    Abstract [en]

    Identification of settlement cues for marine fouling organisms opens up new strategies and methods for biofouling prevention, and enables the development of more effective antifouling materials. To this end, the settlement behaviour of zoospores of the green alga Ulva linza onto cationic oligopeptide self-assembled monolayers (SAMs) has been investigated. The spores interact strongly with lysine- and arginine-rich SAMs, and their settlement appears to be stimulated by these surfaces. Of particular interest is an arginine-rich oligopeptide, which is effective in attracting spores to the surface, but in a way which leaves a large fraction of the settled spores attached to the surface in an anomalous fashion. These 'pseudo-settled' spores are relatively easily detached from the surface and do not undergo the full range of cellular responses associated with normal commitment to settlement. This is a hitherto undocumented mode of settlement, and surface dilution of the arginine-rich peptide with a neutral triglycine peptide demonstrates that both normal and anomalous settlement is proportional to the surface density of the arginine-rich peptide. The settlement experiments are complemented with physical studies of the oligopeptide SAMs, before and after extended immersion in artificial seawater, using infrared spectroscopy, null ellipsometry and contact angle measurements.

  • 4.
    Ederth, Thomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Pettitt, M E
    University of Birmingham.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Du, Chun-Xia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Ekblad, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Zhou, Ye
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Falk, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Callow, M E
    University of Birmingham.
    Callow, J A
    University of Birmingham.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Interactions of Zoospores of Ulva linza with Arginine-Rich Oligopeptide Monolayers2009In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, no 16, p. 9375-9383Article in journal (Refereed)
    Abstract [en]

    We recently reported oil the strong interactions of zoospores of the green alga, Ulva linza with all arginine-rich oligopeptide self-assembled monolayer (SAM) [Biofouling 2008, 24, 303-312], where the arginine-rich peptide induced not only high spore settlement, but also a form of abnormal settlement, or "pseudo-settlement", whereby it proportion of spores do not go through the normal process of surface exploration, adhesive exocytosis, and loss of flagella. Further. it was demonstrated that both the total number of settled spores and the fraction of pseudosettled spores were related to the surface density of the arginine-rich peptide. Here we present a further investigation of the interactions of zoospores of ulva with a set of oligomeric, de nom designed, arginine-rich peptides, specifically aimed to test the effect of peptide primary structure on the interaction. Via variations in the peptide length and by permutations in the amino acid sequences, we gain further insight into the spore-surface interactions. The interpretation of the biological assays is supported by physicochemical characterization of the SAMs using infrared spectroscopy, ellipsometry, and contact angle measurement. Results confirm the importance of arginine residues for the anomalous pseudosettlement, and we found that settlement is modulated by variations in both the total length and peptide primary structure. To elucidate the Causes of the anomalous settlement and the possible relation to peptide-membrane interactions, we also compared the settlement of the "naked" zoospores of Ulva(which present it lipoprotein membrane to the exterior without a discrete polysaccharide cell wall), with the settlement of diatoms (unicellular algae that are surrounded by it silica cell wall), onto the peptide SAMs. Cationic SAMs do not notably affect settlement (attachment), adhesion strength, or viability of diatom cells, Suggesting that the effect of the peptides on zoospores of Ulva is mediated via specific peptide-membrane interactions.

  • 5.
    Johansson, Leif B. G.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Bäck, Marcus
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Lantz, Linda
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Eriksson, Mikaela
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Nilsson, Peter R.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    A variety of thiophene based ligands for detection of protein aggregates by surface plasmon resonanceManuscript (preprint) (Other academic)
    Abstract [en]

    By attaching an azide functional group via a tetraethylene glycol linker to the α-terminal position of a variety of oligothiophenes, thiophene-based ligands that can be utilized for detection of protein aggregates with surface plasmon resonance have been developed. All ligands displayed selectivity towards recombinant amyloid fibrils and the LCO/protein aggregate interaction could be detected by fluorescence as well as by surface plasmon resonance.

  • 6.
    Jonsson, Bengt-Harald
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology .
    Broo, Klas
    Lundqvist, Martin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology .
    Nygren, Patrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Design of Functional Peptide-Nanoparticle Complexes with Potential Applications in Targeted Drug Delivery2008In: BITs 6th annual congress of 2008 International drug discovery science and technology,2008, 2008, p. 142-143Conference paper (Other academic)
  • 7.
    Lundqvist, Martin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Jonsson, Bengt-Harald
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Broo, Klas
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle2006In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 45, no 48, p. 8169-8173Article in journal (Refereed)
    Abstract [en]

    No abstrack available.

  • 8.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    De Novo Design and Characterization of Surface Binding Peptides - Steps toward Functional Surfaces2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The ability to create surfaces with well-defined chemical properties is a major research field. One possibility to do this is to design peptides that bind with a specific secondary structure to silica nanoparticles. The peptides discussed in this thesis are constructed to be random coil in solution, but are “forced” to become helical when adsorbed to the particles. The positively charged side-chains on the peptides strongly disfavor an ordered structure in solution due to electrostatic repulsion. When the peptides are introduced to the particles these charges will strongly favor the structure because of ion pair bonding between the peptide and the negatively charged nanoparticles. The peptide-nanoparticle system has been thoroughly investigated by systematic variations of the side-chains. In order to determine which factors that contributes to the induced structure, several peptides with different amino acid sequences have been synthesized. Factors that have been investigated include 1) the positive charge density, 2) distribution of positive charges, 3) negative charge density, 4) increasing hydrophobicity, 5) peptide length, and 6) by incorporating amino acids with different helix propensities. Moreover, pH dependence and the effect of different nanoparticle curvature have also been investigated. It will also be shown that the system can be modified to incorporate a catalytic site that is only active when the helix is formed. This research will increase our understanding of peptide-surface interactions and might be of importance for both nanotechnology and medicine.

    List of papers
    1. Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle
    Open this publication in new window or tab >>Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle
    2006 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 45, no 48, p. 8169-8173Article in journal (Refereed) Published
    Abstract [en]

    No abstrack available.

    Keywords
    Amino acids, catalysis, helical structures, nanoparticles, peptides
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-14548 (URN)10.1002/anie.200600965 (DOI)
    Available from: 2008-02-25 Created: 2008-02-25 Last updated: 2017-12-13Bibliographically approved
    2. Optimizing Nanoparticle Induced Helical Structure in a De Novo Designed Peptide by Rational Changes in Amino Acid Sequence
    Open this publication in new window or tab >>Optimizing Nanoparticle Induced Helical Structure in a De Novo Designed Peptide by Rational Changes in Amino Acid Sequence
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:liu:diva-14549 (URN)
    Available from: 2008-02-25 Created: 2008-02-25 Last updated: 2010-01-13
  • 9.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Structural and Functional Studies of De Novo Designed Peptides at Surfaces2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work presented in this thesis deals with the structural and functional properties of peptides at surfaces. The interaction of peptides with surfaces is an ever so common occurrence in our every day life, from the bug squashed on the windshield of our car to the barnacle on our boat, and from the blood plasma used in the hospital to the proteins in our cells. The effect these occurrences has on our lives is diverse, the bug is annoying whereas the barnacle settlement of ship hull is costly for marine transportation, the blood plasma contains components of vital importance for our immunological defense system and the proteins in our cells are crucial for regulatory processes and life.One part of this thesis, performed as a part of the EU-founded project AMBIO, deals with the concept of marine biofouling. A number of short peptides have been designed, synthesized, and used to investigate their effect on the settlement on marine biofoulers, such as the Ulva linza algae and the Navicula diatom, on template surfaces coated with thin layers of these molecules. The surfaces have been thoroughly investigated with respect of their physio-chemical properties before and after submersion in artificial seawater and ultimately in suspensions containing the organisms. The most interesting results were obtained with an arginine-rich peptide coating that when introduced to Ulva linza zoospores, displayed extensive settlement, compared to reference surfaces. In addition, a large fraction of the settled spores had an abnormal morphology.The other part of this thesis is focused on designed peptides that when adsorbed on a negatively charged surface adopts a well-defined secondary structure, either α-helical or β-sheet. Precisely placed amino acids in the peptides will strongly disfavor structure in solution, primarily due to electrostatic repulsion, but when the peptides are adsorbed on the negatively charged surfaces, they adopt a well-defined secondary structure due to ion pair bonding. These interactions have been thoroughly investigated by systematic variations of the side-chains. In order to determine the factors contributing to the induced structure, several peptides with different amino acid sequences have been synthesized. Factors that have been investigated include 1) the positive charge density, 2) distribution of positive charges, 3) negative charge density, 4) increasing hydrophobicity, and 5) incorporating amino acids with different helix propensities. Moreover, pH dependence and the effect of different interaction partners have also been investigated. It has also been shown that the system can be modified to incorporate a catalytic site that is only active when the helix is formed. This research will increase our understanding of peptide-surface interactions and might be of importance for both bionanotechnology and medicine.

    List of papers
    1. Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle
    Open this publication in new window or tab >>Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle
    2006 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 45, no 48, p. 8169-8173Article in journal (Refereed) Published
    Abstract [en]

    No abstrack available.

    Keywords
    Amino acids, catalysis, helical structures, nanoparticles, peptides
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-14548 (URN)10.1002/anie.200600965 (DOI)
    Available from: 2008-02-25 Created: 2008-02-25 Last updated: 2017-12-13Bibliographically approved
    2. Fundamental Design Principles That Guide Induction of Helix upon Formation of Stable Peptide−Nanoparticle Complexes
    Open this publication in new window or tab >>Fundamental Design Principles That Guide Induction of Helix upon Formation of Stable Peptide−Nanoparticle Complexes
    2008 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, no 7, p. 1844-1852Article in journal (Refereed) Published
    Abstract [en]

    We have shown that it is possible to design a peptide that has a very low helical content when free in solution but that adopts a well-defined helix when interacting with silica nanoparticles. From a systematic variation of the amino acid composition and distribution in designed peptides, it has been shown that the ability to form helical structure upon binding to the silica surface is dominated by two factors. First, the helical content is strongly correlated with the net positive charge on the side of the helix that interacts with the silica, and arginine residues are strongly favored over lysine residues in these positions. The second important factor is to have a high net negative charge on the side of the helix that faces the solution. Apparently, both attractive and repulsive electrostatic forces dominate the induction and stabilization of a bound helix. It is also evident that using amino acids that have high propensity to form helix in solution are also advantageous for the formation of helix on surfaces.

    National Category
    Other Basic Medicine
    Identifiers
    urn:nbn:se:liu:diva-15015 (URN)10.1021/nl080386s (DOI)
    Available from: 2008-10-09 Created: 2008-10-09 Last updated: 2018-01-12Bibliographically approved
    3. Secondary Structure in de Novo Designed Peptides Induced by Electrostatic Interaction with a Lipid Bilayer Membrane
    Open this publication in new window or tab >>Secondary Structure in de Novo Designed Peptides Induced by Electrostatic Interaction with a Lipid Bilayer Membrane
    Show others...
    2010 (English)In: LANGMUIR, ISSN 0743-7463, Vol. 26, no 9, p. 6437-6448Article in journal (Refereed) Published
    Abstract [en]

    We show that it is possible to induce a defined secondary structure in de nova designed peptides upon electrostatic attachment to negatively charged lipid bilayer vesicles without partitioning of the peptides into the membrane, and that the secondary structure can be varied via small changes in the primary amino acid sequence of the peptides. The peptides have a random-coil conformation in solution, and results from far-UV circular dichroism spectroscopy demonstrate that the structure induced by the interaction with silica nanoparticles is solely alpha-helical and also strongly pH-dependent. The present study shows that negatively charged vesicles, to which the peptides are electrostatically adsorbed via cationic amino acid residues, induce either alpha-helices or beta-sheets and that the conformation is dependent on both lipid composition and variations in peptide primary structure. The pH-dependence of the vesicle-induced peptide secondary structure is weak, which correlates well with small differences in the vesicles electrophoretic mobility, and thus the surface charge, as the pH is varied.

    Place, publisher, year, edition, pages
    ACS American Chemical Society, 2010
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-56297 (URN)10.1021/la100027n (DOI)000276969700056 ()
    Note

    The previous status of this article was Manuscript.

    Available from: 2010-05-07 Created: 2010-05-07 Last updated: 2017-01-11
    4. Anomalous settlement behavior of Ulva linza zoospores on cationic oligopeptide surfaces
    Open this publication in new window or tab >>Anomalous settlement behavior of Ulva linza zoospores on cationic oligopeptide surfaces
    Show others...
    2008 (English)In: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 24, no 4, p. 303-312Article in journal (Refereed) Published
    Abstract [en]

    Identification of settlement cues for marine fouling organisms opens up new strategies and methods for biofouling prevention, and enables the development of more effective antifouling materials. To this end, the settlement behaviour of zoospores of the green alga Ulva linza onto cationic oligopeptide self-assembled monolayers (SAMs) has been investigated. The spores interact strongly with lysine- and arginine-rich SAMs, and their settlement appears to be stimulated by these surfaces. Of particular interest is an arginine-rich oligopeptide, which is effective in attracting spores to the surface, but in a way which leaves a large fraction of the settled spores attached to the surface in an anomalous fashion. These 'pseudo-settled' spores are relatively easily detached from the surface and do not undergo the full range of cellular responses associated with normal commitment to settlement. This is a hitherto undocumented mode of settlement, and surface dilution of the arginine-rich peptide with a neutral triglycine peptide demonstrates that both normal and anomalous settlement is proportional to the surface density of the arginine-rich peptide. The settlement experiments are complemented with physical studies of the oligopeptide SAMs, before and after extended immersion in artificial seawater, using infrared spectroscopy, null ellipsometry and contact angle measurements.

    Keywords
    Fouling, algae, self-assembled monolayers, cationic peptides, Ulva, spore
    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:liu:diva-15018 (URN)10.1080/08927010802192650 (DOI)
    Available from: 2008-10-09 Created: 2008-10-09 Last updated: 2017-12-11
    5. Interactions of Zoospores of Ulva linza with Arginine-Rich Oligopeptide Monolayers
    Open this publication in new window or tab >>Interactions of Zoospores of Ulva linza with Arginine-Rich Oligopeptide Monolayers
    Show others...
    2009 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, no 16, p. 9375-9383Article in journal (Refereed) Published
    Abstract [en]

    We recently reported oil the strong interactions of zoospores of the green alga, Ulva linza with all arginine-rich oligopeptide self-assembled monolayer (SAM) [Biofouling 2008, 24, 303-312], where the arginine-rich peptide induced not only high spore settlement, but also a form of abnormal settlement, or "pseudo-settlement", whereby it proportion of spores do not go through the normal process of surface exploration, adhesive exocytosis, and loss of flagella. Further. it was demonstrated that both the total number of settled spores and the fraction of pseudosettled spores were related to the surface density of the arginine-rich peptide. Here we present a further investigation of the interactions of zoospores of ulva with a set of oligomeric, de nom designed, arginine-rich peptides, specifically aimed to test the effect of peptide primary structure on the interaction. Via variations in the peptide length and by permutations in the amino acid sequences, we gain further insight into the spore-surface interactions. The interpretation of the biological assays is supported by physicochemical characterization of the SAMs using infrared spectroscopy, ellipsometry, and contact angle measurement. Results confirm the importance of arginine residues for the anomalous pseudosettlement, and we found that settlement is modulated by variations in both the total length and peptide primary structure. To elucidate the Causes of the anomalous settlement and the possible relation to peptide-membrane interactions, we also compared the settlement of the "naked" zoospores of Ulva(which present it lipoprotein membrane to the exterior without a discrete polysaccharide cell wall), with the settlement of diatoms (unicellular algae that are surrounded by it silica cell wall), onto the peptide SAMs. Cationic SAMs do not notably affect settlement (attachment), adhesion strength, or viability of diatom cells, Suggesting that the effect of the peptides on zoospores of Ulva is mediated via specific peptide-membrane interactions.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2009
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-19996 (URN)10.1021/la900688g (DOI)
    Note

    The previous status of this article was Manuscript.

    Available from: 2009-08-24 Created: 2009-08-24 Last updated: 2017-12-13Bibliographically approved
  • 10.
    Nygren, Patrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Lundqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology . Linköping University, The Institute of Technology.
    Broo, Klas
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jonsson, Bengt-Harald
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology . Linköping University, The Institute of Technology.
    Fundamental Design Principles That Guide Induction of Helix upon Formation of Stable Peptide−Nanoparticle Complexes2008In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, no 7, p. 1844-1852Article in journal (Refereed)
    Abstract [en]

    We have shown that it is possible to design a peptide that has a very low helical content when free in solution but that adopts a well-defined helix when interacting with silica nanoparticles. From a systematic variation of the amino acid composition and distribution in designed peptides, it has been shown that the ability to form helical structure upon binding to the silica surface is dominated by two factors. First, the helical content is strongly correlated with the net positive charge on the side of the helix that interacts with the silica, and arginine residues are strongly favored over lysine residues in these positions. The second important factor is to have a high net negative charge on the side of the helix that faces the solution. Apparently, both attractive and repulsive electrostatic forces dominate the induction and stabilization of a bound helix. It is also evident that using amino acids that have high propensity to form helix in solution are also advantageous for the formation of helix on surfaces.

  • 11.
    Nygren, Patrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Lundqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Broo, Klas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Jonsson, Bengt-Harald
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Secondary structure in de novo designed peptides induced by electrostatic interaction with particles and membranes.2011Conference paper (Other academic)
  • 12.
    Nygren, Patrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Lundqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Jonsson, Bengt-Harald
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Secondary Structure in de Novo Designed Peptides Induced by Electrostatic Interaction with a Lipid Bilayer Membrane2010In: LANGMUIR, ISSN 0743-7463, Vol. 26, no 9, p. 6437-6448Article in journal (Refereed)
    Abstract [en]

    We show that it is possible to induce a defined secondary structure in de nova designed peptides upon electrostatic attachment to negatively charged lipid bilayer vesicles without partitioning of the peptides into the membrane, and that the secondary structure can be varied via small changes in the primary amino acid sequence of the peptides. The peptides have a random-coil conformation in solution, and results from far-UV circular dichroism spectroscopy demonstrate that the structure induced by the interaction with silica nanoparticles is solely alpha-helical and also strongly pH-dependent. The present study shows that negatively charged vesicles, to which the peptides are electrostatically adsorbed via cationic amino acid residues, induce either alpha-helices or beta-sheets and that the conformation is dependent on both lipid composition and variations in peptide primary structure. The pH-dependence of the vesicle-induced peptide secondary structure is weak, which correlates well with small differences in the vesicles electrophoretic mobility, and thus the surface charge, as the pH is varied.

  • 13.
    Wetterö, Jonas
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rheumatology.
    Hellerstedt, T.
    Nygren, Patrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Broo, K.
    Occupational and Environmental Medicine, Sahlgrenska University Hospital, Göteborg University, Göteborg, Sweden.
    Aili, Daniel
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Immobilized chemoattractant peptides mediate adhesion and distinct calcium-dependent cell signaling in human neutrophils2008In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, no 13, p. 6803-6811Article in journal (Refereed)
    Abstract [en]

    Chemotaxis is the stimulated directional migration of cells in response to chemotactic factors, manifested for instance during leukocyte interaction with chemoattractants in inflammation. The N-formyl-Met-Leu-Phe (fMLF) bacterial peptide family is particularly potent in attracting and activating neutrophilic granulocytes. To accomplish defined circumstances for recruitment and activation of cells, we fabricated semitransparent gold-coated glass coverslips functionalized with chemoattractant fMLF receptor peptide agonist analogues. Peptides based on a common leading four-amino-acid sequence Gly-Gly-Gly-Cys were thus coupled to two potent fMLF receptor agonists, N-formyl-Tyr-Nle-Phe-Leu- Nle-Gly-Gly-Gly-Cys and N-formyl-Met-Leu-Phe-Gly-Gly-Gly-Cys, and a formylated control peptide, N-formyl-Gly-Gly-Gly-Cys. They were anchored via the SH group of Cys either directly to the gold surface or a mixed self-assembled monolayer composed of maleimide- and hydroxyl-terminated oligo(ethylene glycol) alkyldisulfides. The overall peptide immobilization procedure was characterized with ellipsometry, contact angle measurement, and infrared spectroscopy. When exposed to granulocytes, the agonist surface rapidly recruited neutrophils and the cells responded with extensive spreading and intracellular calcium transients within minutes. The reference peptide generated no such activation, and the cells maintained a more spherical morphology, suggesting that we have been able to immobilize chemoattractant receptor agonist peptides with retained bioactivity. This is a crucial step in designing surfaces with specific effects on cellular behavior. © 2008 American Chemical Society.

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