Influence of Tyrosine-Derived Moieties and Drying Conditions on the Formation of Helices in Gelatin

Abstract

The single and triple helical organization of protein chains strongly influences the mechanical properties of gelatin-based materials. A chemical method for obtaining different degrees of helical organization in gelatin is covalent functionalization, while a physical method for achieving the same goal is the variation of the drying conditions of gelatin solutions. Here we explored how the introduction of desaminotyrosine (DAT) and desaminotyrosyl tyrosine (DATT) linked to lysine residues of gelatin influenced the kinetics and thermodynamic equilibrium of the helicalization process of single and triple helices following different drying conditions. Drying at a temperature above the helix-to-coil transition temperature of gelatin (T > T(c), called v(short)) generally resulted in gelatins with relatively lower triple helical content (X(c,t) = 1-2%) than lower temperature drying (T < T(c), called v(long)) (X(c,t) = 8-10%), where the DAT(T) functional groups generally disrupted helix formation. While different helical contents affected the thermal transition temperatures only slightly, the mechanical properties were strongly affected for swollen hydrogels (E = 4-13 kPa for samples treated by v(long) and E = 120-700 kPa for samples treated by v(short)). This study shows that side group functionalization and different drying conditions are viable options to control the helicalization and macroscopic properties of gelatin-based materials.

Structural reinforcement and failure analysis in composite nanofibers of graphene oxide and gelatin

“…The integrated intensity of the first reflection can be used as a measure of the degree of renaturation, or triple-helix content, of gelatin films [7]. In particular, herein the relative amount of triple helices (X) within the samples has been determined by dividing the integrated intensity of this reflection by that of the broad peak associated to peptide bonds [36]. The comparison of the XRD patterns reported in Fig.…”

Biocompatibility and inflammatory response in vitro and in vivo to gelatin-based biomaterials with tailorable elastic properties

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A gelatin based antioxidant enriched biomaterial by grafting and saturation: Towards sustained drug delivery from antioxidant matrix

“…Molar ellipticity is often used in far UV-vis CD measurement to reflect the fact that peptide bond in protein is optically active to absorb left and right handed circularly polarized light slightly differently. Gelatin, in general, is a heterogeneous mixture of single or multi-stranded polypeptides, each with extended left-handed proline helix [43]. Initially CD was run for blank and grafted gelatin samples to find out any significance difference in conformation of secondary structures (Fig.…”