1 / 36

Self-Organizing Bio-structures

Self-Organizing Bio-structures. NB2-2008 L. Duroux. Lecture 7. Protein-based nanomaterials. 1. Peptide-based nanostructures. A first insight into SA peptides. Concept of peptide SA introduced by Ghadiri et al. (1993)

xiu
Download Presentation

Self-Organizing Bio-structures

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Self-Organizing Bio-structures NB2-2008 L. Duroux

  2. Lecture 7 Protein-based nanomaterials

  3. 1. Peptide-based nanostructures

  4. A first insight into SA peptides • Concept of peptide SA introduced by Ghadiri et al. (1993) • Synthetic cyclic polypeptides (alternate L- & D-) self-assemble into Ø8-9nm nanotubes • Function as novel antimicrobial agents, drug delivery systems & nanomaterials

  5. Ghadiri’s cyclic polypeptides (CPP)

  6. Electronic microscopy

  7. pH-dependance of CP SA

  8. CPP forming pores in membranes

  9. Self-Assembling Peptide Nanotubes • 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)

  10. SA based on native 2ndary structural motifs

  11. Protein structural motifs & SA designs Amyloid fibrils Type II polyPro helix

  12. SA Fibers engineering based on coiled-coils Woolfson & Ryadnov, 2006

  13. Amyloid peptides • A generic, universal form of protein/peptide aggregation • Cause of many diseases: Altzheimer’s, Type II diabetes, Prions... • Extended b-sheet SA forming fibrils

  14. Nano-object formed by amyloid peptides Object formed Amyloid fibrils (pancreas type II diabetes) Amyloid fibrils Nanotubes Nanospheres

  15. The role of aromatics in amyloid fibrils formation • Phe dipeptide: the recognition core of Altzheimer’s amyloid fibril • Forms nanotubes • Applications in nano-electronics

  16. SA based on amphiphilicity

  17. Structures of peptides used in SA Boloamphiphile Amphiphile Surfactant-like Phenylalanine dipeptide Reches and Gazit, 2006

  18. Peptide nanotubes Applications Nanotubes with Ca-binding and cell-adhesion  bone-like material Idem, non-conjugated Nanofibers forming hydrogel  matrix for tissue regeneration & engineering

  19. Peptide-Amphiphile and Tissue Engineering SA fibers with CCCCGGGS(PO4)PGD: without Ca2+ (a) and Ca2+ (b)

  20. Aromatic dipeptides

  21. Hydrophobic layers made with dipeptides Görbitz, 2006

  22. Types of nanostructures from various dipeptides

  23. SA of Val-Ala class

  24. SA patterns of the Phe-Phe class Phe-Trp Phe-Gly Phe-Leu Phe-Phe

  25. Formation of nanotubes with Phe-Phe dipeptides

  26. 2. Protein-based SA nanotools

  27. S-layer proteins

  28. What are S-Layer proteins? • S stands for surface: glycoprotein subunits forming outer envelope of Bacteria and Archea • Periodic structures with defined physico-chemical properties (pore size) • Self_assemble into 2D layers to form monomolecular lattices: potential in nanobiotechnologies (scaffolds, patterning matrices)

  29. Applications of S-layers • production of isoporous ultrafiltration membranes • supporting structures for defined immobilization or incorporation of functional molecules (e.g. antigens, antibodies, ligands, enzymes) • matrix for the development of biosensors including solid-phase immunoassays and label-free detection systems • Support and stabilizing matrices for functional lipid membranes, liposomes, and emulsomes • adjuvants for weakly immunogenic antigens and haptens • Matrix for controlled biomineralization and structure for formation of ordered arrays of metal clusters or nanoparticles (molecular electronics and nonlinear optics or catalysts)

  30. S-Layer lattices 100nm Gram+ bacterium

  31. Self-Assembled monomolecular layers

  32. S-layer as template for PSA detection

  33. Assembly of lipids on S-layers • Non-covalent bonding • Electrostatic interactions between corrugated (inner) side of S-layer (carboxy groups) and charges on lipid head groups (zwitterions) • 2-3 contact points between protein and lipid: most lipids free to diffuse laterally: semi-rigid membrane

  34. S-layers as support for lipid membranes

  35. Self-Assembly of a ion-channel in S-layers

  36. Expected applications of S-layer-driven SA of lipid membranes • Life Sciences: • Drug delivery • Diagnostics • Biosensors • Chemistry and material sciences • Bio-mineralization • Non-linear optics • Molecular electronics • Catalysis

More Related