Metal-Promoted Assembly of Two Collagen Mimetic Peptides into a Biofunctional "Spiraled Horn" Scaffold.
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ABSTRACT:
SUBMITTER: Strauss K
PROVIDER: S-EPMC5456626 | biostudies-other | 2016 Oct
REPOSITORIES: biostudies-other
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Project description:The mechanical and biological functions of the native collagens remain an inspiration in materials design, but widespread application of de novo collagens has been limited in part by the need for hydroxylated proline in the formation of stable triple helical structures. To address this continued need and to expand the potential for recombinant expression of functional, hydroxyproline-lacking collagen-mimetic peptides, we have designed a hydrophilic, nonrepetitive, and thermally stable collagen-mimetic peptide via the incorporation of triple-helix-stabilizing charged triplets. The peptide sequence is also equipped with a type III-collagen-mimetic cystine knot at the C-terminus to facilitate covalent cross-linking of the triple helix via simple air oxidation. Circular dichroic spectroscopy (CD) studies of this collagen-mimetic peptide revealed a typical, thermally stable, collagen triple helix signature with a weak positive maximum at 225 nm and a triple helix melting temperature (T(m)) of 35 and 43 degrees C for the reduced and oxidized forms, respectively. The thermal behavior was confirmed via analysis by differential scanning calorimetry. Interestingly, this hydroxyproline-lacking, collagen-mimetic peptide also assembles into nanorods and microfibrillar structures as observed via transmission electron microscopy. The identification and demonstrated useful collagen-mimetic properties of this peptide suggests important opportunities in the recombinant design of new collagen-based biomaterials.
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Project description:Self-assembly of artificial peptides has been widely studied for constructing nanostructured materials, with numerous potential applications in the nanobiotechnology field. Herein, we report the synthesis and hierarchical self-assembly of collagen-mimetic peptides (CMPs) bearing various aromatic groups at the N-termini, including 2-naphthyl, 1-naphtyl, anthracenyl, and pyrenyl groups, into nanofibers. The CMPs (R-(GPO)n: n > 4) formed a triple helix structure in water at 4 °C, as confirmed via CD analyses, and their conformations were more stable with increasing hydrophobicity of the terminal aromatic group and peptide chain length. The resulting pre-organized triple helical CMPs showed diverse self-assembly into highly ordered nanofibers, reflecting their slight differences in hydrophobic/hydrophilic balance and configuration of aromatic templates. TEM analysis demonstrated that 2Np-CMPn (n = 6 and 7) and Py-CMP6 provided well-developed natural collagen-like nanofibers and An-CMPn (n = 5-7) self-assembled into rod-like micelle fibers. On the other hand, 2Np-CMP5 and 1Np-CMP6 were unable to form nanofibers under the same conditions. Furthermore, the Py-CMP6 nanofiber was found to encapsulate a guest hydrophobic molecule, Nile red, and exhibited unique emission behavior based on the specific nanostructure. In addition to the ability of CMPs to bind small molecules, their controlled self-assembly enables their versatile utilization in drug delivery and wavelength-conversion nanomaterials.
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