Band Shape of the Circular Dichroism

1971 ◽  
Vol 55 (7) ◽  
pp. 3546-3554 ◽  
Author(s):  
S. H. Lin
Keyword(s):  
Circular Dichroism ◽  
Band Shape ◽  
Circular Dichroïsm

A Solution to the Artifact Problem in Fourier Transform Vibrational Circular Dichroism

1988 ◽  
Vol 42 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Petr Malon ◽  
Timothy A. Keiderling
Keyword(s):  
Fourier Transform ◽  
Circular Dichroism ◽  
Vibrational Circular Dichroism ◽  
Band Shape ◽  
Ft Ir ◽  
Circular Dichroïsm

Using a newly constructed FT-IR vibrational circular dichroism (VCD) instrument, we have found that elimination of the ellipsoidal collection mirror before the detector and its replacement by a lens leads to a significant improvement in the absorption artifact problem seen previously in FT-IR/VCD. In the mid-IR region, we have been able to measure VCD of a single enantiomer for molecules such as α-pinene, 3-methylcyclohexanone, and dimethyltartrate. More importantly, this reduction in artifact level brings the FT-IR/VCD band shape of some particularly-difficult-to-measure bands, such as carbonyl stretches, into better agreement with those found in dispersive measurements. These results imply that the dispersive results are reliable, though of lower resolution than those obtained with the use of FT-IR/VCD.

Interconvertibility of Electronic and Vibrational Circular Dichroism Spectra of Proteins: A Test of Principle Using Neural Network Mapping

1996 ◽  
Vol 50 (5) ◽  
pp. 658-668 ◽  
Author(s):  
Petr Pancoska ◽  
Vit Janota ◽  
Timothy A. Keiderling
Keyword(s):  
Neural Network ◽  
Circular Dichroism ◽  
Principal Component ◽  
Vibrational Circular Dichroism ◽  
Band Shape ◽  
Spectroscopic Information ◽  
Hidden Layer ◽  
Hidden Neurons ◽  
Projection Neural Network ◽  
Circular Dichroïsm

Electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) are compared with respect to their interconvertibility for protein structural studies. ECD and amide I' VCD spectra of 28 proteins were used with a backpropagation projection neural network with one hidden layer to develop a mapping between the two spectral types. After the network converged, the number of neurons in the hidden layer was optimized by principal component analysis of the synaptic weights of the pilot network topology with redundant hidden neurons. Actual prediction of one spectrum from the other for individual proteins was tested by retraining these networks with 28 reduced training sets having one protein systematically left out. Comparison of network-predicted spectra with experimental ones is used to identify those spectral features which are unique in each method. Similarly, the VCD spectra of 23 proteins measured in both D2O and H2O in the amide I region were mapped onto each other with the use of the same type of neural network calculation. The results show that the effects of partial deuteration on the VCD spectra band shape are predictable from the H2O spectra. An analysis of the synaptic weights of the optimized networks was performed which allowed identification of the linear and nonlinear parts of the obtained mappings. Insight into the details of how the neural networks encode and process the spectroscopic information is derived from a spectral representation of these weight matrices.

Characterization of Tamm-Horsfall Urinary Glycoprotein

1973 ◽  
Vol 31 ◽  
pp. 420-421
Author(s):  
John P. Robinson ◽  
J. David Puett
Keyword(s):  
Electron Microscopy ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Quaternary Structure ◽  
Normal Adult ◽  
Morphological Properties ◽  
Adult Males ◽  
Circular Dichroïsm ◽  
Urinary Glycoprotein

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.

Circular dichroism spectra of adsorbed dye-aggregates

1968 ◽  
Vol 65 ◽  
pp. 146-151 ◽  
Author(s):  
G. Scheibe ◽  
O. Wörz ◽  
F. Haimerl ◽  
W. Seiffert ◽  
J. Winkler
Keyword(s):  
Circular Dichroism ◽  
Circular Dichroism Spectra ◽  
Circular Dichroïsm
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