Structure, elastin

The basic unit of elastin structure is tropoelastin, which has a molecular weight of about 72,000 and contains 800-850 amino acid residues. It has been proposed that tropoelastin units are present in the random coil conformation and are extensively cross-linked. This makes such a network kinetically free free to stretch and to recoil. It is the entropy effects that permit the stretched elastin... 

Tanzer ML Collagens and elastin Structure and interactions. Curr Opin Cell Biol 1 968-973, 1989... 

L.B. Sandberg, N.T. Soskel, and J.G. Leslie, Elastin structure, biosynthesis, and relation to disease states. N Engl J Med 304,566-579,1981. 

D.W. Urry, C-H. Luan, and S.Q. Peng, Molecular Biophysics of Elastin Structure, Function and Pathology, in Proceedings of The Ciba Foundation Symposium No. 192, The Molecular Biology and Pathology of Elastic Tissues, John Wiley sons. Ltd., Sussex, UK, pp. 4-30,1995. 

Sandberg LB, Soskel NT, Leslie JG. Elastin structure, biosynthesis and relation to disease state. N Engl J Med 1981 304 556-579. 

Dyksterhuis LB, Baldock C, Lammie D, Wess TJ, Weiss AS. A turning point in elastin structure. Matrix Biol. 2006 25 S17. 

Structural proteins u-Keratin Collagen Elastin Eibroin Proteoglycans... 

Keeley, F.W., Bellingham, C.M., and Woodhouse, K.A., Elastin as a self-organising biomaterial Use of recombinantly expressed human elastin polypeptides as a model system for investigations of structure and self-assembly of elastin, Philos. Trans. R. Soc. Lond. B Biol. Sci., 357, 185-189, 2002. 

The first elastomeric protein is elastin, this structural protein is one of the main components of the extracellular matrix, which provides stmctural integrity to the tissues and organs of the body. This highly crosslinked and therefore insoluble protein is the essential element of elastic fibers, which induce elasticity to tissue of lung, skin, and arteries. In these fibers, elastin forms the internal core, which is interspersed with microfibrils [1,2]. Not only this biopolymer but also its precursor material, tropoelastin, have inspired materials scientists for many years. The most interesting characteristic of the precursor is its ability to self-assemble under physiological conditions, thereby demonstrating a lower critical solution temperature (LCST) behavior. This specific property has led to the development of a new class of synthetic polypeptides that mimic elastin in its composition and are therefore also known as elastin-like polypeptides (ELPs). 

Fig. 4 Structures and formation routes of crosslinks in elastin. In the first step, lysine is catalyti-cally converted to allysine by lysyl oxidase all subsequent condensation steps are spontaneous...

This coacervation process forms the basis for the self-assembly, which takes place prior to the crosslinking. The assembly of tropoelastin is based on an ordering process, in which the polypeptides are converted from a state with little order to a more structured conformation [8]. The insoluble elastic fiber is formed via the enzymatic crosslinking of tropoelastin (described in Sect. 2.1). Various models have been proposed to explain the mechanism of elasticity of the elastin fibers. 

Resilin and elastin, unlike other structural proteins, fulfill both definitions of an elastic material. Colloquially speaking, resilin and elastin are stretchy or flexible. They also fulfill the strict definition of an elastic material, i.e., the ability to deform in proportion to the magnitude of an applied stress without a loss of energy, and the recovery of the material to its original state when that stress is removed. Resilin and elastin are alone in the category of structural proteins (e.g., collagen, silk, etc.) in that they have the correct blend of physical properties that allow the proteins to fulfill both definitions of elasticity. Both proteins have high extensibility and combine that property with remarkable resilience [208]. 

Elastin is a structural protein with outstanding properties, and therefore it has inspired many investigations, with special interest in its elastomeric properties. This behavior can be mimicked with ELPs and these have found wide application in... 

Miao M, Cirulis JT, Lee S et al (2005) Structural determinants of cross- linking and hydrophobic domains for self-assembly of elastin-like polypeptides. Biochemistry 44 14367-14375... 

Reiersen H, Clarke AR, Rees AR (1998) Short elastin-like peptides exhibit the same temperature-induced structural transitions as elastin polymers implications for protein engineering. J Mol Biol 283 255-264... 

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