Synchrotron radiation circular dichroism (SRCD) is an emerging technique in structural biology with particular value in protein secondary structure analyses since it permits the collection of data down to much lower wavelengths than conventional circular dichroism (cCD) instruments. Reference database spectra collected on different SRCD instruments in the future as well as current reference dat...

In membranes, the chirality of the amphiphile constituents is sometimes expressed at a supramolecular scale of nanometers or micrometers. We have recently reported that membranes of nonchiral dicationic n-2-n amphiphiles can also be chirally twisted upon interacting with chiral tartrate counterions. Here, we demonstrate that the mechanism of the chiral induction by counterions involves specific...

We report the observation of a magnetic moment on vanadium embedded in copper. Using x-ray-absorption spectroscopy and x-ray magnetic circular dichroism we show that the vanadium atomic magnetic moment is strongly dependent on the formation temperature of the VCu alloy. The absorption spectra allow us to distinguish the electronic transitions which are the signature of the magnetic state from t...

background: recently, botulinum neurotoxin (bont)-derived recombinant proteins have been suggested as potential botulism vaccines. here, with concentrating on bont type e (bont/e), we studied two of these binding domain-based recombinant proteins: a multivalent chimer protein, which is composed of bont serotypes a, b and e binding subdomains, and a monovalent recombinant protein, which contains...

Four new acetylenes (1-4) and one new unsaturated ω-hydroxy fatty acid (5), together with 5 known analogues, were isolated from an aqueous extract of Codonopsis pilosula roots. Their structures were determined by spectroscopic and chemical methods. The new acetylenes are categorized as an unusual cyclotetradecatrienynone (1), tetradecenynetriol (2), and rare octenynoic acids (3 and 4), respecti...

This article presents SOMCD, an improved method for the evaluation of protein secondary structure from circular dichroism spectra, based on Kohonen's self-organizing maps (SOM). Protein circular dichroism (CD) spectra are used to train a SOM, which arranges the spectra on a two-dimensional map. Location in the map reflects the secondary structure composition of a protein. With SOMCD, the predic...

Using the density functional full-potential linearized augmented plane wave approach, the x-ray absorption and magnetic circular dichroism (XMCD) spectra of Ga(1-x)Mn x As are calculated. Significantly, XMCD of Mn is highly sensitive to the change in environment, and thus can be utilized to characterize impurity distribution. The nature of Mn-induced spin polarization on Ga and As sites, vital ...

We present measurements of the spin and orbital magnetic moments of Fe3O4 by using SQUID and magnetic circular dichroism in soft x-ray absorption. The measurements show that Fe3O4 has a noninteger spin moment, in contrast to its predicted half-metallic feature. Fe3O4 also exhibits a large unquenched orbital moment. Calculations using the local density approximation including the Hubbard U metho...

Here, we report the mechanisms of chiral transfer at various length scales in the self-assembly of enantiomeric chiral block copolymers (BCPs*). We show the evolution of homochirality from molecular chirality into phase chirality in the self-assembly of the BCPs*. The chirality of the molecule in the BCP* is identified from circular dichroism (CD) spectra, while the handedness of the helical co...

We present a unified interpretation of experimentally observed magnetic circular dichroism (MCD) in the ferromagnetic semiconductor (Ga,Mn)As, based on theoretical arguments, which demonstrates that MCD in this material arises primarily from a difference in the density of spin-up and spin-down states in the valence band brought about by the presence of the Mn impurity band, rather than being pr...