Chain length effects of oligo(L-lysine)-shelled dendrimers on interaction with DNA.

The interaction of novel oligo(L-lysine)-shelled dendrimers (G3-PLL) with DNA was studied by means of circular dichroism spectroscopy, dynamic light scattering, and melting behavior of double-stranded DNA. G3-PLLs having various oligo(L-lysine) (PLL) segment (n = 5-40) were successfully synthesized by graft-polymerization of L-lysine NCA initiated with amino groups at the 3rd-generation poly(amidoamine) dendrimer surface. The ionization property of the newly prepared G3-PLLs were first examined.

pH-responsive, self-assembling nanoparticle from a fullerene-tagged poly(L-glutamic acid) and its superoxide dismutase mimetic property.

In this study, we describe the fabrication of novel fullerene-containing peptide-nanoparticles through self-assembly. A water-soluble, poly(l-glutamic acid)-attached fullerene was newly synthesized and the conformation and self-assembling property in water were examined by using circular dichroism, FTIR, UV, atomic force microscopy, and dynamic light scattering measurements. In the lower pH region (<6.

Preparation of helical peptide monolayer-coated gold nanoparticles.

We describe herein the preparation of polypeptide (poly(gamma-benzyl-L-glutamate)) monolayer-covered gold nanoparticles (PBLG(n)SS-Au). Two types of PBLG(n)SS having PBLG segment length n=20 and 50 were synthesized and successfully attached to the gold nanoparticle surface using the Brust-Schiffern method. The mean sizes of PBLG(n)SS-Au particles and their gold cluster cores in CHCl3, which were evaluated by means of dynamic light scattering and TEM, respectively, demonstrated that the gold cluster surfaces were covered with PBLG monolayers, and their conformation was found to be mainly in alpha-helix on the basis of FT-IR spectroscopy.

Enantioselective binding and stable encapsulation of alpha-amino aids in a helical poly(L-glutamic acid)-shelled dendrimer in aqueous solutions.

A novel water-soluble peptide-shelled dendrimer containing a poly(L-glutamic acid) segment grafted on the third-generation poly(amido amine) dendrimer was successfully synthesized, and its secondary structural properties and interaction with alpha-amino acids (Trp, Phe, and Tyr) were revealed by spectroscopic measurements. In the lower pH region, this peptide-dendrimer adopted an alpha-helix conformation with almost 100 % helicity resulting from the three-dimensional aggregation of the segment. Interactions with alpha-amino acids proceeded with positive cooperativity on the basis of a Hill plot, and as a result, D isomers preferentially bound to the alpha-helical segments relative to L isomers.

Interaction between polylysine monolayer and DNA at the air-water interface.

The interaction of a polylysine amphiphile, which consists of a poly-L- or -D-lysine (1L or 1D) segment and two long alkyl chains at the C-terminus, with polynucleotides was studied with respect to the highly organized structure of polylysine assemblies on water. The results of surface pressure-area isotherm measurement showed that both of 1L and 1D formed stable monolayers on water in a neutral pH region. The secondary structure of polylysine segment for the surface monolayer was examined by means of circular dichroism and Fourier transform infrared spectroscopies.