Elastin sequence

Faury, G., Gamier, S., Weiss, A. S., Wallach, J., Fulop, T., Jr, Jacob, M. P., Mecham, R. P., Robert, L., and Verdetti, J. (1998). Action of tropoelastin and synthetic elastin sequences on vascular tone and on free Ca2+ level in human vascular endothelial cells. Circ. Res. 82, 328-336. 

Sequence annotation is derived from the elastin sequence database (ElastoDB). 

Figm 13 (a) Sequence and schematic representation of the self-assembly of an amphiphilic diblock elastin polypeptide into core-shell nanoparticles. Elastin-mimetic protein polymers that comprise fusions of elastin sequences with different 7, values can be induced to undergo self-assembly at a temperature between the two transition temperatures, (b) Differential scanning calorimetry measurements indicate an endothermic transition for the more hydrophobic (lower 7 block with a value that corresponds to those observed for the burial of hydro-phobic residues within a folded protein, (c) This transition coincides with the formation of spherical assemblies in which the more hydrophobic block is confined within the micellar core. Transmission electron microscopy measurements are consistent with spherical micelles and more complex assemblies. Reprinted from Lee, T. A. T. Cooper, A. Apkarian, R. P. Conticello, V. P. Adv. Mater. 2000, f2(15), Copyright 2000, with... 

Elizabeth et al. [108] reported an elastin-mimic polypeptide sequence that mimics triblock copolymers (ABA) with the sequence of the respective blocks as... 

Coacervation occurs in tropoelastin solutions and is a precursor event in the assembly of elastin nanofibrils [42]. This phenomenon is thought to be mainly due to the interaction between hydro-phobic domains of tropoelastin. In scanning electron microscopy (SEM) picmres, nanofibril stmc-tures are visible in coacervate solutions of elastin-based peptides [37,43]. Indeed, Wright et al. [44] describe the self-association characteristics of multidomain proteins containing near-identical peptide repeat motifs. They suggest that this form of self-assembly occurs via specific intermolecular association, based on the repetition of identical or near-identical amino acid sequences. This specificity is consistent with the principle that ordered molecular assembhes are usually more stable than disordered ones, and with the idea that native-like interactions may be generally more favorable than nonnative ones in protein aggregates. 

Fig. 15 Amino acid sequences of artificial extracellular matrix (aECM) proteins. Each protein contains a TV tag, a histidine tag, a cleavage site, and elastin-like domains with lysine residues for crosslinking. The RGD cell-binding domain is found in aECM 1, whereas aECM 3 contains the CS5 cell-binding domain. aECM 2 and aECM 4 are the negative controls with scrambled binding domains for aECM 1 and aECM 3, respectively. Reprinted from [121] with permission from American Chemical Society, copyright 2004...

Elastin confers extensibihty and elastic recoil on tissues. Elastin lacks hydroxylysine, Gly-X-Y sequences, triple hehcal stmcture, and sugars but contains desmosine and isodesmosine cross-links not found in collagen. 

Figure 1 Design of a crosslinkable amino acid sequence based on the elastin-mimetic repeat Lys-25.

Elastin-mimetic protein polymers have been fabricated into elastic networks primarily via y-radiation-induced, radical crosslinking of the material in the coacervate state [10]. Although effective, this method cannot produce polymers gels of defined molecular architecture, i.e., specific crosslink position and density, due to the lack of chemoselectivity in radical reactions. In addition, the ionizing radiation employed in this technique can cause material damage, and the reproducibility of specimen preparations may vary between different batches of material. In contrast, the e-amino groups of the lysine residues in polymers based on Lys-25 can be chemically crosslinked under controllable conditions into synthetic protein networks (vide infra). Elastic networks based on Lys-25 should contain crosslinks at well-defined position and density, determined by the sequence of the repeat, in the limit of complete substitution of the amino groups. 

Figure 2 DNA monomer design for elastin-mimetic repeat sequenee Lys-25 (the upper strand of the duplex represents the eoding sequence of the monomer in the 5 -3 direction).

Calcium in this case would coordinate with acyl oxygens from the polypeptide backbone of the protein, because of its unique amino acid sequences and potential conformations348). Non-polar peptides have been isolated from elastin which consists almost entirely of the three non-polar amino acids glycine, valine, and proline349). Portions of porcine tropoelastin have been partially sequenced350). Repeating tetra-, penta-, and hexapeptides have been observed. The tetrapeptide contains the sequence —Gly—Gly—L—Val—L—Pro— the pentapeptide —L—Val—L—Pro-... 

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