Supramolecular amyloid-like assembly of the polypeptide sequence coded by exon 30 of human tropoelastin.
Elastin is known to self-aggregate in twisted-rope filaments. However, an ultrastructural organization different from the fibrils typical of elastin, but rather similar to those shown by amyloid networks, is shown by the polypeptide sequence encoded by exon 30 of human tropoelastin. To better understand the molecular properties of this sequence to give amyloid fibers, we used CD, NMR, and FTIR (Fourier transform infrared spectroscopy) to identify the structural characteristics of the peptide. In this study, we have demonstrated, by FTIR, that antiparallel beta-sheet conformation is predominant in the exon 30 fibers. These physical-chemical studies were combined with transmission electron microscopy and atomic force microscopy to analyze the supramolecular structure of the self-assembled aggregate. These studies show the presence of fibrils that interact side-by-side probably originating from an extensive self-interaction of elemental cross beta-structures. Similar sequences, of the general type XGGZG(X, Z = V, L, A, I), are widely found in many proteins such as collagens IV and XVII, major prion protein precursor, amyloid beta A4 precursor protein-binding family, etc., thus suggesting that this sequence could be involved in contributing to the self-assembly of amyloid fibers even in other proteins.
Tamburro
Antonio Mario
AM
Department of Chemistry, Università della Basilicata, Via N. Sauro 85, 85100 Potenza, Italy.
Pepe
Antonietta
A
Bochicchio
Brigida
B
Quaglino
Daniela
D
Ronchetti
Ivonne Pasquali
IP
D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry; D002942:Circular Dichroism; D004396:Coloring Agents / Q000494:pharmacology; D003224:Congo Red / Q000494:pharmacology; D004549:Elastin / Q000737:chemistry; D005091:Exons; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D017550:Spectroscopy, Fourier Transform Infrared; D014333:Tropoelastin / Q000737:chemistry* / Q000235:genetics*
D000682:Amyloid; D004396:Coloring Agents; D010455:Peptides; D014333:Tropoelastin; D003224:Congo Red; D004549:Elastin