AFM Study of the Elastin-like Biopolymer Poly(ValGlyGlyValGly)

Abstract

In this paper, we report an AFM study on the supramolecular structures adopted by the synthetic polypentapeptide poly(ValGlyGlyValGly), whose monomeric sequence is an abundant, simple building block of elastin. The polypeptide was analyzed by deposition from both methanolic and aqueous suspensions, showing different behaviors. In methanol, the polypeptide is able to evolve, in a time-dependent way, from layers to ribbons to beaded filaments. When the equilibrium is reached, the formation of well-defined dendritic structures is also observed. This restructuring of the polypentapeptide seems to be reminiscent of a sort of Rayleigh instability. When deposited from aqueous suspensions, the polypeptide self-assembles either in fibrillar networks or in amyloid-like patterns, both of them being found in elastin or elastin-related polypeptides. As a general finding, poly(ValGlyGlyValGly) seems to constitute an excellent mimetic of the supramolecular properties of native elastin.

Charge transport and intrinsic fluorescence in amyloid-like fibrils

“…The length of the fibrils varied from hundreds of nanometers to several microns. Tamburro and colleagues (29) recently reported that the filament length of the analogue poly(ValGlyGlyValGly) peptide can reach 70 m, suggesting a possible mechanism of longitudinal alignment of the peptides besides a lateral one. Repeated AFM imaging performed over the same sample at different times (up to several months after sample preparation) revealed no significant morphological changes, indicating a remarkable stability of the fibrils at ambient conditions, which is in qualitative agreement with our previous data on solid-state protein films (30,31).…”

“…The polypentapeptides poly( ValGly GlyLeuGly) and poly(ValGlyGlyValGly) were chemically synthesized according to the procedures previously developed by Tamburro and colleagues (29,34).…”

“…Fibrils were generated by suspending the dry powder peptide at a concentration of 1.0 mg/ml in Milli-Q water (Millipore Corporation, Billerica, MA) and incubating the solution in a vial tube for 3-5 weeks at 27°C to obtain mature amyloid-like fibrils (29). AFM Measurements.…”

Supramolecular Amyloid-like Assembly of the Polypeptide Sequence Coded by Exon 30 of Human Tropoelastin

“…Quite interestingly, the elastin-like biopolymer poly(VGGVG), which comprises the sequences LGGLG and VGGLG similar to those contained in EX30 peptide, has been shown to self-assemble in an amyloidlike pattern when deposited from aqueous suspensions (59). The fibrils did not solubilize after dilution, indicating the irreversibility of the process, also in this case.…”

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

“…[1][2][3][4] These interactions must be controlled to derive information on the aggregation phenomena occurring in important pathologies as amyloidosis, and indeed used, to ensure successful manufacturing of engineered bio-structures. [5][6][7] Such considerations have been of strength in our work on the formation of strong and stiff amyloid-like and non-amyloid fibers or agglomerates from elastin-like polypeptides (ELPs), poly (ValGlyGlyValGly), [8][9][10] and poly(ValGlyGlyLeuGly). [11][12][13] Using AFM to compare the macromolecular structures of these ELPs from aqueous and non-aqueous suspension we have found that the ratio of amyloid-like fibers depends on the water activity in the medium.…”