Self-Assembly of Synthetic and Biological Polymeric Systems of ...

Contents
5.1
5.2
5.3
5.4
5.5
5.1.1
5.1.2
5.1.3
5.1.4
5.2.1
5.2.2
5.2.3
5.2.4
5.3.1
5.3.2
5.5.1
Protein structure
Primary structure of the proteins
Secondary structure of the proteins
Tertiary structure of the proteins
Quaternary structure of the proteins
Protein aggregation
Unfolded state
Intermediate and transition state assembles
Native state
Energy landscape: protein aggregation
Amyloid fibrils
5.1.- Protein structure
Amyloid fibrils hallmarks
Kinetic fibril formation in vitro
Human serum albumin
Amyloid fibrils as biomaterials
Hen egg-white lysozyme
CHAPTER 5
Proteins
From a chemical point of view, proteins are linear heteropolymers whose backbones are
usually composed of almost 20 different monomers, as opposed to most synthetic polymers
which are composed of one or few monomers. Whilst polymers have a large extended
organization in aqueous solution, proteins fold as relatively small compacted structures. The
spatial arrangement of atoms in a protein is called conformation. The possible conformations
of a protein include any structural state which can achieve without breaking covalent bonds. A
change in conformation could occur, for example, by rotation about single bonds. The
conformations existing under a given set of conditions are usually those most
thermodynamically stable, i.e. having the lowest Gibbs energy.
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