Self organizing bio structures
1 / 36

Self-Organizing Bio-structures - PowerPoint PPT Presentation

  • Uploaded on
  • Presentation posted in: General

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)

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Self-Organizing Bio-structures


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)

  • Synthetic cyclic polypeptides (alternate L- & D-) self-assemble into Ø8-9nm nanotubes

  • Function as novel antimicrobial agents, drug delivery systems & nanomaterials

Ghadiri’s cyclic polypeptides (CPP)

Electronic microscopy

pH-dependance of CP SA

CPP forming pores in membranes

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)

SA based on native 2ndary structural motifs

Protein structural motifs & SA designs

Amyloid fibrils

Type II polyPro helix

SA Fibers engineering based on coiled-coils

Woolfson & Ryadnov, 2006

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

Nano-object formed by amyloid peptides

Object formed

Amyloid fibrils (pancreas type II diabetes)

Amyloid fibrils



The role of aromatics in amyloid fibrils formation

  • Phe dipeptide: the recognition core of Altzheimer’s amyloid fibril

  • Forms nanotubes

  • Applications in nano-electronics

SA based on amphiphilicity

Structures of peptides used in SA






Reches and Gazit, 2006

Peptide nanotubes


Nanotubes with Ca-binding and cell-adhesion  bone-like material

Idem, non-conjugated

Nanofibers forming hydrogel  matrix for tissue regeneration & engineering

Peptide-Amphiphile and Tissue Engineering

SA fibers with CCCCGGGS(PO4)PGD: without Ca2+ (a) and Ca2+ (b)

Aromatic dipeptides

Hydrophobic layers made with dipeptides

Görbitz, 2006

Types of nanostructures from various dipeptides

SA of Val-Ala class

SA patterns of the Phe-Phe class





Formation of nanotubes with Phe-Phe dipeptides

2. Protein-based SA nanotools

S-layer proteins

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)

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)

S-Layer lattices


Gram+ bacterium

Self-Assembled monomolecular layers

S-layer as template for PSA detection

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

S-layers as support for lipid membranes

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

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

  • Login