Structure of the Elastic Fiber: An Overview.

Abstract

Intense research efforts over the past 18 yr have probed deeply into the structure of the elastic fiber. This began with the elucidation of the demosine crosslinks in elastin and the description of the elastin precursor, tropoelastin, derived from copper-deficient animals. Characterization of the precursor material indicates that it is a single polypeptide chain of approximately 800 amino acid residues containing lysine residues in clusters destined to form the desmosine crosslinks. The molecule contains large areas of hydrophobic sequence interspersed with shorter stretches of polyalanine and the lysines. The shorter structures may be folded into alpha-helices. The larger hydrophobic areas appear to form a unique structure known as the beta spiral which possesses elastometric properties. Inside the hydrophobic areas repeating sequences such as the pentapeptide pro-gly-val-gly-val have been observed the exact significance of which is not appreciated, but it appears to be well-conserved between species. Recent studies in the molecular biology of this protein have indicated that it is synthesized on the rough ER with a short leader sequence of about 25 residues. This is lost before the tropoelastin is exported. Diversity in sequence studies in these leaders suggest that there may be two elastins, type A and B, which vary with the maturation of the animal.

Bladder smooth muscle organ culture preparation maintains the contractile phenotype

“…The viscoelastic properties of the bladder are primarily dependent on the elements contained within the extracellular matrix (4, 64). Elastin, for example, is very compliant compared with collagen (32,45). Elastin contributes mainly to the foot of the passive length-tension curve, while the sharp rising portion reflects the collagen component.…”

Early preclinical diagnosis of dominant pseudoxanthoma elasticum by specific ultrastructural changes of dermal elastic and collagen tissue in a family at risk

“…Particular aberrations as, for example, "collagen flowers" are not unique to any one disorder, but are also found, for example, in the Ehlers-Danlos syndrome group and in osteogenesis imperfecta. Otherwise, different osmiophilic inclusions during aging or actinic changes of elastin fibers have been described (Stadler and Orfanos 1978;Danielsen 1979;Sandberg et al 1982;Stadler 1989). a-c Electron microscopy of aberrant collagen fibrils with flower-like or serrated, thickened cross-sections (arrows) in the middle dermis, a M.R.…”

The borohydride-reducible compounds of human aortic elastin. Demonstration of a new cyclic amino acid in alkali hydrolysate, and changes with age and in patients with annulo-aortic ectasia including one with Marfan syndrome

“…The cyclization reaction presumes that the ACP is the N-terminal amino acid. The cross-linking sites of elastin of young tissues are surrounded by alanine, tyrosine and glycine residues (Sandberg et al, 1982;Rucker & Murray, 1978;Foster et al, 1973) of elastin has given variable results depending on the purification procedure used (Gotte, 1980). As far as we know, lysine has not been reported to be the N-terminal amino acid of tropoelastin.…”

“…It is extensively cross-linked and metabolically quite inert. The precursor, tropoelastin, is secreted into the extracellular space and cross-linked into insoluble elastin (Sandberg et al, 1982). The cross-linking begins by an enzymic step catalysed by lysyl oxidase (Pinnell & Martin, 1968;Eyre et al, 1984) to form lysine aldehydes.…”