Naturally inspired peptides

Responsive peptides that are derived from naturally inspired motifs fall into two categories. First, responsive polypeptides can be prepared based on the structure of elas-tin, an extracellular matrix protein that is found in connective tissue such as skin and arteries (MacEwan Chilkoti, 2010). These materials typically respond to a stimulus through a change in conformation of the polymer. The second category of naturally inspired peptides consists of short peptide sequences that represent substrates for enzymes. In these materials, the change induced by the stimulus (the enzyme) is an alteration of the chemical functionality displayed on the material surface. Both response mechanisms are shown in Figure 3.4. 

Figure 34 Response mechanisms for naturally inspired peptide surfaces, (a) Phase transition and (h) surface chemistry.

This chapter introduced the nature-inspired polymers with the ability to mimic cell activity for advanced drug and gene delivery. These polymers have been combined with biomolecules such as carbohydrates, peptides, and proteins, which played the prominent roles not only of excellent drug carriers but also of drug molecules themselves. For further... 

Responsive peptide surfaces may originate from biologically inspired peptide sequences or they may be artificially designed based on our knowledge of the interactions of amino acids within a peptide chain. Both classes will be discussed here. Naturally inspired responsive peptide surfaces are based either on a protein mimic (a long peptide sequence that mimics the properties of a responsive protein) or on... 

This field has also inspired the development of a range of pseudo-peptides, that is polyamides composed of amino acids other than a-amino acids. These include for instance peptoids, /9-amino acid oligomers and also compounds such as peptide nucleic acids and DNA binding polyamides, all of which share the amide (peptide) chemistry with natural peptides. 

In recent years, developments in high-throughput screening inspired many pharmaceutical companies to focus and rely on combinatorial chemistry, especially massive parallel synthesis, to find new lead structures. The employed chemistry is often simple and the concept depends on sheer numbers for success. The main research areas were heterocyclic and peptide chemistry, and the resulting structures often lacked complexity and diversity, and most importantly the chance to utilize the evolutionary advantage of natural products with their privileged structures. 

Straightforward, versatile, and generates libraries of macrocyclic pseudo peptides with unprecedent functional and skeletal diversity. For example, natural product-inspired biaryl ether-cyclopeptoid macrocycles were obtained by this methodology [98, 99]. 

Paul van der Schoot, Nucleation and Co-Operativity in Supramolecular Polymers Michael J. McPherson, Kier James, Stuart Kyle, Stephen Parsons, and Jessica Riley, Recombinant Production of Self-Assembling Peptides Boxun Leng, Lei Huang, and Zhengzhong Shao, Inspiration from Natural Silks and Their Proteins Sally L. Gras, Surface- and Solution-Based Assembly of Amyloid Fibrils for Biomedical and Nanotechnology Applications... 

In the rapidly expanding area of nanochemistry, chemists often use Nature as inspiration to create their systems and in trying to mimic Nature, both in the efficiency and the perfection of the structures a number of natural building blocks have already been incorporated into synthetic materials. We have already reviewed how structurally simple natural building blocks (such as lipids, amino acids, peptides, carbohydrates and natural polymers)... 

So far, peptide synthesis has mainly involved the preparation of biologically or pharmaceutically relevant substances, total chemical synthesis of natural proteins or protein engineering. The objective of this chapter is to show how the different methods that have been developed for peptide synthesis can be used to prepare biologically-inspired supramolecular architectures and polymeric materials, which might be of potential interest for a variety of advanced applications. 

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