Search

The design and surface-binding characterization of a de novo designed peptide, JAK1, which undergoes surface-induced folding at the hydroxyapatite (HA)-solution interface, is described. The results have shown that the peptide remains unfolded and monomeric in solution under normal physiological conditions while circular dichroism (CD) spectroscopy has indicated that in the presence of hydroxyapatite the peptide avidly binds to the mineral surface adopting a helical structure.

Effects of arsenic binding on [Beta]-hairpin are studied by introducing pairs of cysteines into a model monomeric [Beta]-hairpin to yield a family of peptides. Results reveal that arsenic binding could both favor and disfavor helical and [Beta]-hairpin structures depending on the placement of cysteine residues and the plasticity of the secondary structural elements to insertion of a monoalkylated As(III) derivative.

Study is conducted to show that light could be use as a trigger to initiate peptide folding and consequent self-assembly. This is achieved by covalently incorporating a cytocompatible photocleavable moiety that electrostatically inhibits peptide folding and intermolecular self-assembly process that leads to hydrogel formation.

Three Fmoc-protected acids, mono-, di-, and trimethylated diaminopropionic acid derivatives are designed such that each additional methyl moiety covalently incorporated at the side-chain nitrogen serves to increase the hydrophobicity of the residue. The utility of these residues is explored through the construction of buried salt bridges into the coiled coil scaffold of GCN4-p1.

As(III) displays a wide range of effects in cellular chemistry. Model alpha-helical peptides containing two cysteine (Cys) residues in various sequential arrangements and spatial locations is utilized to study the structural effects of arsenic binding.

A chemically and mechanically responsive material is constructed through a peptide design. It is found that the chemical responsiveness is due to the linking of intramolecular folding and intermolecular assembly and the mechanical responsiveness is due to the self-assembled nature of the hydrogel scaffold.

A study was conducted to characterize a series of alpha-helical C-capping auxiliaries supporting various chain lengths based on alkyldiamines and monoguanylated diamines. A sedimentation equilibrium ultracentrifugation analysis was carried out on a peptide to show that is was monomeric in nature. Results indicated that D-Arginine can be effectively incorporated at any position within a peptide or protein sequence.

The preparation of four 6,6'-bis(acylamino)-2,2'-bipyridine-based amino acids involves the coordination of Cu(II) complexes. The coordination replaces the i + 1 and i + 2 residues of the beta-turn in the amino acids. The four 6,6'-bis(acylamino)-2,2'-bipyridine-based amino acids consist of several peptides with amino acids incorporated at different levels.

The preparation and de novo design of peptides capable of undergoing a thermally triggered [beta]-strand-swapped self-assembly event leading to hydrogel formation is described. The study demonstrates the use of [beta]-strand-swapping to fabricate biomaterials with tunable fibril nanostructure and bulk hydrogel rheological properties.

The inherent antibacterial activity of a peptide-based [beta]-hairpin hydrogel is discussed. The hydrogen surface is found to be highly active against the Gram-positive, as well as Gram-negative bacteria.

A new synthetic peptide is formed which self assembles into beta sheet fibrils and shows a straight stacked morphology. Moreover, the existence of a diproline peptide between two beta sheets that form strands in peptide series is illustrated to be a significant element to promote the straight laminated fibril morphology.

The design and utility of a peptidic probe capable of accurately measuring environmental redox potential through sensitized emission is presented. A probe that contains residues, which strongly favor turn formation, should favor disulfide bond formation resulting in a probe characterized by a low reduction potential and vice versa.

Click chemistry represents a modular approach toward synthesis that uses only the most practical chemical transformations to make molecular connections with excellent fidelity. The introduction of azide and alkyne groups into organogelator compounds and the cross-linking of their noncovalent polyvalent networks by the copper catalyzed cycloaddition of alkynes and azides (CuAAC) reaction is described.

A small, de novo designed peptide (MAX3) that exhibits complete thermoreversible self-assembly into a hydrogel network has been described. Results indicate that with higher temperature the peptide undergoes a unimolecular folding event, giving an amphiphilic beta-hairpin that consequently self-assembles into a hydrogel network.

The use of linear beta-peptides for the design of biologically active peptides is described.

An interior salt bridge has been successfully buried into the helix/helix interface of a peptide spanning the homodimeric coiled coil of GCN4 (GCN4-p1). The physical characteristics of GCN4-p1 and two molecular modifications are assessed. The buried single salt bridge is highly specific for heterodimer formation under some thermodynamic conditions. The buried salt bridge on GCN4-based peptides is illustrated. Experimental observations are discussed.

Provides information on a study focusing on the design of efficient ...-helical c-capping auxiliaries with various chain lengths based on alkyldiamines and monoguanylated diamines. Methodology used to conduct the study; Results of the study; Discussion on the results.

Among several important considerations for implantation of a biomaterial, a main concern is the introduction of infection. We have designed a hydrogel scaffold from the self-assembling peptide, MAX1, for tissue regeneration applications whose surface exhibits inherent antibacterial activity. In experiments where MAX1 gels are challenged with bacterial solutions ranging in concentrations from 2 × 103 colony forming units (CFUs)/dm2 to 2 × 109 CFUs/dm2, gel surfaces exhibit broad-spectrum antibacterial activity. Results show that the hydrogel surface is active against Gram-positive (Staphylococcus epidermidis, Staphylococcus aureus, and Streptococcus pyogenes) and Gram-negative (Kiebsiella pneumoniae and Escherichia coli) bacteria, all prevalent in hospital settings. Live—dead assays employing laser scanning confocal microscopy show that bacteria are killed when they engage the surface. In addition, the surface of MAX1 hydrogels was shown to cause inner and outer membrane disruption in experiments that monitor the release of β-galactosidase from the cytoplasm of lactose permease-deficient E. coli ML-35. These data suggest a mechanism of antibacterial action that involves membrane disruption that leads to cell death upon cellular contact with the gel surface. Although the hydrogel surface exhibits bactericidal activity, co-culture experiments indicate hydrogel surfaces show selective toxicity to bacterial versus mammalian cells. Additionally, gel surfaces are nonhemolytic toward human erythrocytes, which maintain healthy morphologies when in contact with the surface. These material attributes make MAX1 gels attractive candidates for use in tissue regeneration, even in nonsterile environments. [ABSTRACT FROM AUTHOR]

The article describes the introduction of azide and alkyne groups into organogelator compounds and the cross-linking of their noncovalent polyvalent networks by the copper(I)-catalyzed azide-alkyne [3+2] cycloaddition. Low molecular weight organogelators based on the undecylamide of trans-1,2-diaminocyclohexane are used. Rheological measurements confirmed the viscoelastic nature of the gels.