Statistical accuracy test in measurements of circular dichroism

1979 ◽  
Vol 44 (4) ◽  
pp. 1312-1317 ◽  
Author(s):  
Petr Pančoška ◽  
Ivo Frič ◽  
Karel Bláha
Keyword(s):  
Circular Dichroism ◽  
Statistical Methods ◽  
Spectral Range ◽  
Probable Error ◽  
Statistical Accuracy ◽  
Sample Concentration ◽  
Accuracy Test ◽  
Circular Dichroïsm ◽  
Intensity Reading

A collection of one hundred circular dichroism measurements (in acetonitrile) of the model cyclohexapeptide cyclo(glycyl-L-phenylalanyl-L-leucyl-glycyl-L-leucyl-L-phenylalanyl) has been evaluated using standard statistical methods. The reproducibility of the experimental intensity values is discussed with respect to the sample concentration and the particular regions of the CD curve. The maximum probable error in the intensity reading varies with wavelength from ±20 to ±10 000 deg cm2 dmol-1 in the spectral range from 274 to 196 nm, i.e. by 5-15% of the observed intensity.

scholarly journals UV-CD12: synchrotron radiation circular dichroism beamline at ANKA

2015 ◽  
Vol 22 (3) ◽  
pp. 844-852 ◽  
Author(s):  
Jochen Bürck ◽  
Siegmar Roth ◽  
Dirk Windisch ◽  
Parvesh Wadhwani ◽  
David Moss ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Lipid Bilayers ◽  
Spectral Range ◽  
Signal To Noise Ratio ◽  
Linear Dichroism ◽  
Water Soluble ◽  
Protein Films ◽  
Hydrated Protein ◽  
Circular Dichroïsm

Synchrotron radiation circular dichroism (SRCD) is a rapidly growing technique for structure analysis of proteins and other chiral biomaterials. UV-CD12 is a high-flux SRCD beamline installed at the ANKA synchrotron, to which it had been transferred after the closure of the SRS Daresbury. The beamline covers an extended vacuum-UV to near-UV spectral range and has been open for users since October 2011. The current end-station allows for temperature-controlled steady-state SRCD spectroscopy, including routine automated thermal scans of microlitre volumes of water-soluble proteins down to 170 nm. It offers an excellent signal-to-noise ratio over the whole accessible spectral range. The technique of oriented circular dichroism (OCD) was recently implemented for determining the membrane alignment of α-helical peptides and proteins in macroscopically oriented lipid bilayers as mimics of cellular membranes. It offers improved spectral quality <200 nm compared with an OCD setup adapted to a bench-top instrument, and accelerated data collection by a factor of ∼3. In addition, it permits investigations of low hydrated protein films down to 130 nm using a rotatable sample cell that avoids linear dichroism artifacts.

Protamines. VII. Circular Dichroism Study of Salmine A I

1981 ◽  
Vol 36 (3-4) ◽  
pp. 305-309 ◽  
Author(s):  
G. M. Bonora ◽  
F. Bertanzon ◽  
V. Moretto ◽  
C. Toniolo
Keyword(s):  
Aqueous Solution ◽  
Circular Dichroism ◽  
Statistical Methods ◽  
Basic Protein ◽  
Helical Conformation ◽  
Counter Ions ◽  
Conformational Preferences ◽  
Main Components ◽  
The Right ◽  
Circular Dichroïsm

Salmine A I, one of the components of the protamine from salmon, has been purified and characterized. The conformational preferences of salmine A I have been examined as a function of pH, added salts, presence of helix-supporting solvents, and temperature, using circular dichroism. It has been found that this small basic protein adopts predominantly an unordered conformation in aqueous solution. Addition of counter-ions, in particular perchlorate, and 2-chloroethanol induces to various extents the onset of the right-handed α-helical conformation. The results are discussed in comparison with those previously reported on the three main components of clupeine, the protamine from herring, and with the published conformational predictions by various statistical methods

Analysis of a Polarizing Michelson Interferometer for Dual Beam Fourier Transform Infrared, Circular Dichroism Infrared, and Reflectance Ellipsometric Infrared Spectroscopies

1981 ◽  
Vol 35 (2) ◽  
pp. 186-193 ◽  
Author(s):  
M. J. Dignam ◽  
M. D. Baker
Keyword(s):  
Fourier Transform ◽  
Circular Dichroism ◽  
Spectral Range ◽  
Michelson Interferometer ◽  
Fourier Transform Infrared ◽  
Beam Splitters ◽  
Dual Beam ◽  
Metal Grid ◽  
Ft Ir ◽  
Circular Dichroïsm

The properties of a Fourier transform infrared (FT-IR) spectrometer designed around a polarizing Michelson interferometer (PMI) are analyzed with respect to applications in both conventional absorption as well as polarization spectroscopies. The PMI design is that of Martin and Puplett and consists of a metal grid polarizing beam splitter combined with rooftop retromirrors set to rotate the polarization direction in each beam by 90°. If used in conjunction with additional grid polarizers, positioned according to application, the result is an FT-IR instrument that can function both as a dual beam absorption spectrometer and as a polarization spectrometer. Operating in the former mode, the instrument is predicted to achieve speeds comparable to those achievable using a nonpolarizing dual beam Michelson interferometer but to cover a much wider spectral range due to the achromatic nature of metal grid polarizing beam splitters. In the latter mode, it is predicted to give at least double the effective throughput achievable with conventional instruments equipped with external polarization modulating optics, and again to cover a much wider spectral range. It would extend the capability of determining circular dichroism spectra into the far IR (down to ∼3 cm−1) for the first time. With the development of a process for forming a metal grid polarizer of fine spacing (∼0.1 μm) on a KBr substrate, the instrument would be capable of covering the spectral range 25 000 to 3 cm−1 or lower using only two beam splitters, i.e., in two ranges: 25 000 to 450 cm−1 using a KBr-supported metal grid, and 600 to 3 cm−1 or less using an unsupported wire grid.

An instrument for measuring circular dichroism simultaneously at all wavelengths in a limited spectral range

1991 ◽  
Vol 62 (8) ◽  
pp. 1912-1915 ◽  
Author(s):  
K. Andert ◽  
W. Schälike ◽  
B. Nölting ◽  
R. Pittelkow ◽  
R. Wetzel ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Spectral Range ◽  
Circular Dichroïsm

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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