Search

A unique cyclic peptide structure, 'helix triangle', is reported as a unique example of peptide-based molecular architecture. The cyclic peptide is designed to have a triangular shape in which three 9mer helical peptide units make the sides and three pyrene derivatives make the apexes.

The bicomponent self-assembled monolayers (SAMS) are formed by incorporation of helical peptides into the alkanethiol monolayer, and are characterized by Fourier transform infrared reflection-adsorption spectroscopy (FTIR RAS) and scanning tunneling microscopy (STM). FTIR RAS spectra indicate that the helical peptides are incorporated into the defects in the alkanethiol SAM without disturbing the film structure.

Tetrathiafulvalene (TTF) and chloranil were introduced at the side chains of different cyclic tripeptides, which were self‐assembled into peptide nanotubes (PNTs). PNTs were used as scaffolds for alignment of the charge‐transfer complexes between TTF and chloranil, and they were prepared via two methods, one is that mixing a PNT comprising only TTF with a PNT comprising only chloranil (method 1), and the other is that one pot mixing of cyclic tripeptides with TTF and cyclic tripeptides with chloranil to be self‐assembled into PNTs (method 2). These PNTs naturally associated to form PNT bundles. The surface potentials of the PNT bundles became larger for the PNTs carrying charge‐transfer complexes along the PNT (method 2) than those between PNTs (method 1). This bundle of PNT carrying charge‐transfer complexes along the PNT (method 2) showed a hysteresis response in the piezoelectric force curve with varying bias voltages according to piezoelectric force microscope measurements. [ABSTRACT FROM AUTHOR]

A novel cyclic conjugate of a helical decapeptide and oligo(phenyleneethynylene) (OPE) is prepared. Molecular simulation using time dependent-density functional theory has shown a right-handed twist conformation of the OPE moiety for the negative Cotton effect and the conjugate has provided a new way to obtain a [pi]-conjugated compound having main-chain chirality.

A novel molecular system where photocurrent direction could be reversibly switched between anodic and cathodic by changing the pH of the solution is reported. A highly ordered self-assembled monolayer (SAM) is prepared on gold where an N-ethylcarbozolyl (ECz) group and a carboxyl group are located at the monolayer surface.

Octadecapeptides carrying a ferrocene moiety at the molecular terminal are self-assembled on gold, and long-range electron transfer from the ferrocene moiety to gold is investigated by electrochemical methods. Effects on electron transfer of dipole moment of helical peptides, linkers connecting the peptide to gold, and chromophores introduced into the side are discussed.

A helical hexadecapeptide immobilized on gold through a thiophenyl group at the N-terminal is analyzed by scanning tunneling microscopy under ultrathin vacuum to obtain the I-V response at a molecular level. The molecular rectification behavior is due to the ferrocene unit regulating the direction of the electron transfer at the metal-molecule junction.

The well-ordered self assembled monolayers (SAMs) from helical peptides carrying a Fc group at the N- or C-terminal end is prepared and a long-range electron transfer (ET) reaction over 4nm, which is accompanied by the oxidation of the Fc moiety is observed. Electrochemical measurements reveal that the ET reaction is predominantly governed by the inelastic hopping mechanism.

A novel host molecular assembly of a free-standing flat nanosheet with compartmentalized spaces was prepared using a bolaamphiphilic peptide composed of two amphiphilic helical peptides and an oligo(naphthaleneethynylene) (ONE) unit at the center of the molecule. The nanosheet possesses void host spaces that can accommodate two mol-equivalent ONE groups to form columns of ONE groups in a right-handed helical way and ONE channels over a long distance. The present molecular system therefore can provide a chiral pore channel for relatively large molecules. [ABSTRACT FROM AUTHOR]

A novel method, which explains the synthesis of glycosaminoglycan using a transition state analogue monomer, is reported. The glycosaminoglycan used in the study is hyaluronan, which is a natural polysacharide.