Poly(glutamic acid) has been studied with a nanosecond T-jump experiment. A new experimental set-up based on the frequency-quadrupling of an 82 MHz Titanium-Sapphire laser allows rapid CD measurements to be performed. Combining time-resolved absorption and circular dichroism at 204 and 220 nm, we are able to measure precisely the unfolding relaxation time as well as the helical fraction evoluti...

Soft X-ray natural circular dichroism (CD) of amino acids is studied by means of ab initio methods. Several approaches to evaluate the oscillator and rotary strengths of core-tovalence excitations are compared from the viewpoint of basis set dependence. It was shown that, among considered methods, the random phase approximation (RPA) provides most consistent and less time-consuming results for ...

A short peptide corresponding to the alpha-helical region of BPTI shows partial folding in aqueous solution (pH 7) as judged by circular dichroism (CD). Folding is temperature and denaturant sensitive, and the peptide is monomeric. The difference CD spectrum, obtained from spectra at two temperatures, indicates that the peptide folds as an alpha-helix. Difference CD spectroscopy provides a sens...

The magnetic circular dichroism (MCD) associated with the visible d-d electronic transitions of Co(I1) alkaline phosphatase between 400 and 650 nm are similar in the acid form, the alkaline form, and the phosphate and arsenate complexes of the enzyme. Thus similar coordination geometries must exist in all forms of the enzyme. The MCD suggests that this geometry is that of a distorted tetrahedro...

Circular dichroism (CD) is widely used in the structural characterization and secondary structure determination of proteins. The vacuum UV region (below 190 nm), where charge-transfer transitions have an influence on the CD spectra, can be accessed using synchrotron radiation circular dichroism (SRCD) spectroscopy. Recently, charge-transfer transitions in a conformationally diverse set of dipep...

The ability to accurately measure or predict several physicochemical properties of molecules which play a role as active substances in drugs can be strategic importance for pharmacological applications, addition its possible interest fundamental research. Chirality is relevant feature the characterization drug molecules: enantiomers show different activity and adverse effects. separate stereois...

The surface parameter of nanoparticles such as hydrophobicity and a hydrophilicity on protein structure and function is very important. In this study, conformational changes of glucose oxidase (GOx) in the mercaptopurine: GNPs and 11-mercaptoundecanoic acid: GNPs as a hydrophobic and a hydrophilic GNPs surface was investigated by various spectroscopic techniques, including: UV-Vis absorption, f...

The origin of the nonconservative nature of the circular dichroism (CD) spectrum of bacteriochlorophyll dimers is investigated. It is shown that coupling between the Qy and Qx transitions can, under rather restricting circumstances, lead to an asymmetrical CD spectrum: only for a limited set of relative orientations of the monomers within the dimer is the spectrum found to be asymmetrical. The ...

Circular dichroism (CD) spectroscopy is a powerful technique employed to study the structure of biomolecules. More accurate calculation CD from first principles will aid both computational and experimental studies protein dynamics. We apply diabatisation scheme improve description nearest neighbour interactions between two electronic transitions (n?* ?nb?*) localised on each individual peptide ...