self-organizing bio- structures nb2-2008 l. duroux
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Self-Organizing Self-Organizing Bio-structuresBio-structures
NB2-2008NB2-2008
L. DurouxL. Duroux
Lecture 7Lecture 7
Protein-based nanomaterialsProtein-based nanomaterials
1. Peptide-based 1. Peptide-based nanostructuresnanostructures
A first insight into SA A first insight into SA peptidespeptides
Concept of peptide SA introduced by Concept of peptide SA introduced by Ghadiri et al. (1993)Ghadiri et al. (1993)
Synthetic cyclic polypeptides (alternate Synthetic cyclic polypeptides (alternate L- & D-) self-assemble into Ø8-9nm L- & D-) self-assemble into Ø8-9nm nanotubesnanotubes
Function as novel antimicrobial agents, Function as novel antimicrobial agents, drug delivery systems & nanomaterialsdrug delivery systems & nanomaterials
Ghadiri’s cyclic Ghadiri’s cyclic polypeptides (CPP)polypeptides (CPP)
Electronic microscopyElectronic microscopy
pH-dependance of CP SApH-dependance of CP SA
CPP forming pores in CPP forming pores in membranesmembranes
cyclic-peptides self-assembled into open tubes
consist of an even number of alternated D / L amino acids
formation of anti-parallel hydrogen bonded network
assembly could be controlled by electrostatic interactions
assembly could be directed toward particular environments (hydrophobic) by selection of amino acids
are functional material (ion channel & antibiotic)
Self-Assembling Peptide Nanotubes
SA based on SA based on native 2native 2ndaryndary
structural motifsstructural motifs
Protein structural motifs & SA Protein structural motifs & SA designs designs
Type II polyPro helixAmyloid fibrils
SA Fibers engineering based SA Fibers engineering based on coiled-coilson coiled-coils
Woolfson & Ryadnov, 2006
Amyloid peptidesAmyloid peptides
A generic, universal form of A generic, universal form of protein/peptide aggregationprotein/peptide aggregation
Cause of many diseases: Cause of many diseases: Altzheimer’s, Type II diabetes, Altzheimer’s, Type II diabetes, Prions...Prions...
Extended Extended -sheet SA forming fibrils-sheet SA forming fibrils
Nano-object formed by Nano-object formed by amyloid peptidesamyloid peptides
Object formed
Amyloid fibrils (pancreas type II diabetes)
Amyloid fibrils
Nanotubes
Nanospheres
The role of aromatics in The role of aromatics in amyloid fibrils formationamyloid fibrils formation
Phe dipeptide: the recognition core of Altzheimer’s amyloid fibril
Forms nanotubes
Applications in nano-electronics
SA based on SA based on amphiphilicityamphiphilicity
Structures of peptides used Structures of peptides used in SAin SA
Reches and Gazit, 2006
Boloamphiphile
Amphiphile
Surfactant-like
Phenylalaninedipeptide
Peptide nanotubes Peptide nanotubes
Applications
Nanotubes with Ca-binding and cell-adhesion bone-like material
Idem, non-conjugated
Nanofibers forming hydrogel matrix for tissue regeneration & engineering
Peptide-Amphiphile and Peptide-Amphiphile and Tissue EngineeringTissue Engineering
SA fibers with CCCCGGGS(PO4)PGD: without Ca2+ (a) and Ca2+ (b)
Aromatic Aromatic dipeptidesdipeptides
Hydrophobic layers made with Hydrophobic layers made with dipeptidesdipeptides
Görbitz, 2006
Types of nanostructures Types of nanostructures from various dipeptidesfrom various dipeptides
SA of Val-Ala classSA of Val-Ala class
SA patterns of the Phe-SA patterns of the Phe-Phe classPhe class
Phe-Trp Phe-Gly
Phe-Leu Phe-Phe
Formation of nanotubes Formation of nanotubes with Phe-Phe dipeptideswith Phe-Phe dipeptides
2. Protein-based 2. Protein-based SA nanotoolsSA nanotools
S-layer proteinsS-layer proteins
What are S-Layer What are S-Layer proteins?proteins?
S stands for surface: glycoprotein subunits S stands for surface: glycoprotein subunits forming outer envelope of Bacteria and Archeaforming outer envelope of Bacteria and Archea
Periodic structures with defined physico-Periodic structures with defined physico-chemical properties (pore size)chemical properties (pore size)
Self_assemble into 2D layers to form Self_assemble into 2D layers to form monomolecular lattices: potential in monomolecular lattices: potential in nanobiotechnologies (scaffolds, patterning nanobiotechnologies (scaffolds, patterning matrices)matrices)
Applications of S-layersApplications of S-layers1. production of isoporous ultrafiltration membranes2. supporting structures for defined immobilization or
incorporation of functional molecules (e.g. antigens, antibodies, ligands, enzymes)
3. matrix for the development of biosensors including solid-phase immunoassays and label-free detection systems
4. Support and stabilizing matrices for functional lipid membranes, liposomes, and emulsomes
5. adjuvants for weakly immunogenic antigens and haptens
6. Matrix for controlled biomineralization and structure for formation of ordered arrays of metal clusters or nanoparticles (molecular electronics and nonlinear optics or catalysts)
S-Layer latticesS-Layer lattices
Gram+ bacterium
100nm
Self-Assembled Self-Assembled monomolecular layersmonomolecular layers
S-layer as template for PSA S-layer as template for PSA detectiondetection
Assembly of lipids on S-Assembly of lipids on S-layerslayers
Non-covalent bondingNon-covalent bonding
Electrostatic interactions between Electrostatic interactions between corrugated (inner) side of S-layer corrugated (inner) side of S-layer (carboxy groups) and charges on lipid (carboxy groups) and charges on lipid head groups (zwitterions)head groups (zwitterions)
2-3 contact points between protein 2-3 contact points between protein and lipid: most lipids free to diffuse and lipid: most lipids free to diffuse laterally: semi-rigid membranelaterally: semi-rigid membrane
S-layers as support for lipid S-layers as support for lipid membranesmembranes
Self-Assembly of a ion-Self-Assembly of a ion-channel in channel in
S-layersS-layers
Expected applications of S-Expected applications of S-layer-driven SA of lipid layer-driven SA of lipid
membranesmembranes Life Sciences:Life Sciences:
Drug deliveryDrug delivery DiagnosticsDiagnostics BiosensorsBiosensors
Chemistry and material sciencesChemistry and material sciences Bio-mineralizationBio-mineralization Non-linear opticsNon-linear optics Molecular electronicsMolecular electronics CatalysisCatalysis
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