Fibrous and Helical Calcite Crystals Induced by Synthetic Polypeptides ContainingO‐Phospho‐L‐Serine andO‐Phospho‐L‐Threonine

Abstract

The modification of CaCO(3) crystal growth by synthetic L-Ser(PO(3)H(2)) and L-Thr(PO(3)H(2)) containing polypeptides is described. The amino acids Gly, L-Glu, L-Asp, L-Ser, L-Ala, and L-Lys induced rhombohedral calcite with a rough surface. Dipeptides, Xaa-L-Ser(PO(3)H(2)) (Xaa = Gly, L-Glu, L-Asp, L-Ser, L-Ala and L-Lys) induced vaterite crystals in the lower [Ca(2+)]. On the other hand, L-Ser(PO(3)H(2))-containing polypeptides formed spherical vaterite and fibrous calcite. The characteristic helical calcite was found in the presence of copoly[L-Ser(PO(3)H(2))(75)L-Asp(25)] or poly[L-Ser(PO(3)H(2))(3)-L-Asp]. Fibrous calcite, spherical vaterite, and helical calcite crystals were subjected to XRD and EDX analysis. XRD revealed the specific faces of these crystals. EDX spectra and surface analysis visualized the localization of the polypeptides and CaCO(3) components. Together with TEM and SAED data, we propose hypothetical growth mechanisms for the fibrous and helical calcite crystals.

Wachstumsinduziertes Biegen und Verwinden von Einkristallen

“…[30,205] Vor einiger Zeit wurde behauptet, dass die durch chirale Additive induzierte mesoskopische Verwindung von Kristalliten gesteuert worden sei. [278,279] Allerdings zeigten Kunz und Mitarbeiter, dass die mit SEM beobachteten Calcit-Helices [278,279] stark an die allgegenwärtigen Abschabungen von Kunststoff-Laborausrüstung erinnern, was die Notwendigkeit unterstreicht, repräsentative mikroskopische Aufnahmen zu zeigen und nicht nur die außergewçhnlichste Form aus einer Sammlung. [280]…”

Calcium Phosphate Crystallization on Electrospun Cellulose Non‐Woven Fabrics Containing Synthetic Phosphorylated Polypeptides

“…[9][10][11][12][13] We also previously described the experimental conditions for the CaCO 3 crystallization and developed a hypothesis for the growth mechanism of the characteristic fibrous calcite crystals and the helical calcite based on WXRD, SEM-EDX and selected-area electron diffraction (SAED) analyses.…”

“…Conclusion (iii) will be related to the fact that, in the case of calcium carbonate mineralization, only the copoly[Ser(PO 3 H 2 ) 75 Asp 25 ] induced a characteristic helical calcite crystal in our previous study. [11,13] Although the reason for this is still unclear, however, one possible explanation can be derived from the amino acid composition of the phosphorylated protein as an in vivo crystal growth matrix. For instance, the phosphophoryn is composed of a tandem repeat of the short sequences of Ser(PO 3 H 2 ) and Asp, most likely as ÀSer(PO 3 H 2 )ÀSer (PO 3 H 2 )ÀAspÀ or on occasion, ÀSer(PO 3 H 2 )ÀAspÀ.…”

“…[9][10][11][12][13] The synthetic copolypeptides composed of aspartic acid (Asp) and Ser(PO 3 H 2 ) residues induced several kinds of calcium carbonate crystal morphologies, for example, fibrous and helical calcites and spherical vaterite crystals. [13] These results clearly indicated that the Ser(PO 3 H 2 )-containing polypeptides are an effective crystal growth modifier for the calcium biominerals.…”

“…[9][10][11][12][13] The synthetic copolypeptides composed of aspartic acid (Asp) and Ser(PO 3 H 2 ) residues induced several kinds of calcium carbonate crystal morphologies, for example, fibrous and helical calcites and spherical vaterite crystals. [13] These results clearly indicated that the Ser(PO 3 H 2 )-containing polypeptides are an effective crystal growth modifier for the calcium biominerals. We have also studied the electrospinning process using natural polysaccharides or synthetic poly(amino acid)s. [14] The thin fibers of chitosan, [15,16] poly(g-benzyl-L-glutamate), [17] cellulose [18] and gelatin [19] were successfully prepared using our electrospinning techniques.…”