Microfibrils, components

The amino acid sequence of fibrillin-1 is predominantly hydrophilic, even in the presence of bound calcium (Sherratt et al, 2004). In addition, fibrillin-1 has 14 potential N-glycosylation sites that may contribute to the hydrophilic nature of fibrillin-1, since complex N-linked oligosaccharides are negatively charged if they contain sialic acid. Additional regions of increased hydrophilicity may be contributed by other microfibril components (see Section III below). 

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). 

Replicas of the tomato cell walls are very similar to those of onion parench5una cell walls but replicas of the DCB-adapted walls did not show the structure of the walls clearly. The principle components of the adapted walls are shorter thinner fibres which seemed to form a gel-like structure with little evidence of long cellulosic microfibrils characteristic of the unadapted cells. It is possible that such a gel will bind water more strongly and reduce the amount of etching that takes place, resulting in a less well-defined replica (2). 

Chitin is the microfibrillar component of some fungal cell walls and is equivalent to cellulose microfibrils in plants. It is a characteristic feature of the Ascomycetes, Deuteromycetes and Basidiomycetes but is absent in the Phycomycetes, which contain cellulose as their major cell wall constituent. 

Chitin. Like cellulose synthase, fungal chitin synthases are present in the plasma membrane and extrude microfibrils of chitin to the outside.147 150 In the fungus Mucor the majority of the chitin synthesized later has its N-acetyl groups removed hydrolytically to form the deacetylated polymer chitosan.151152 Chitin is also a major component of insect exoskeletons. For this reason, chitin synthase is an appropriate target enzyme for design of synthetic insecticides.153... 

The primary cell-wall of plants is formed by microfibrils of cellulose in a complex matrix of polysaccharides, proteins, and glycoproteins. The structure and relationship of the different components is under continuous study and revision, and most of them can now be identified and their biosynthesis studied.124"126... 

Fibrillin microfibrils are widely distributed extracellular matrix assemblies that endow elastic and non elastic connective tissues with long-range elasticity. They direct tropoelastin deposition during elastic fibrillogenesis and form an outer mantle for mature elastic fibers. Microfibril arrays are also abundant in dynamic tissues that do not express elastin, such as the ciliary zonules of the eye. Mutations in fibrillin-1—the principal structural component of microfibrils—cause Marfan syndrome, a heritable disease with severe aortic, ocular, and skeletal defects. Isolated fibrillin-rich microfibrils have a complex 56 nm beads-on-a-string appearance the molecular basis of their assembly and... 

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