scholarly journals Calibration and Standardisation of Synchrotron Radiation Circular Dichroism and Conventional Circular Dichroism Spectrophotometers

2003 ◽  
Vol 17 (4) ◽  
pp. 653-661 ◽  
Author(s):  
Andrew J. Miles ◽  
Frank Wien ◽  
Jonathan G. Lees ◽  
A. Rodger ◽  
Robert W. Janes ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Secondary Structure ◽  
Structural Biology ◽  
Optical Rotation ◽  
Protein Secondary Structure ◽  
Reference Database ◽  
Calibration Methods ◽  
Circular Dichroïsm ◽  
Representative Protein

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 datasets derived from cCD spectra must be compatible. Therefore there is a need for standardization of calibration methods to ensure quality control. In this study, magnitude and optical rotation measurements on four cCD and three SRCD instruments were compared at 192.5, 219, 290 and 490 nm. At high wavelengths, all gave comparable results, however, at the lower wavelengths, some variations were observable. The consequences of these differences on the spectrum, and the calculated secondary structure, of a representative protein (myoglobin) are demonstrated. A method is proposed for standardising spectra obtained on any CD instrument, conventional or synchrotron‒based, with respect to existing and future databases.

scholarly journals Calibration and standardisation of synchrotron radiation and conventional circular dichroism spectrometers. Part 2: Factors affecting magnitude and wavelength

2005 ◽  
Vol 19 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Andrew J. Miles ◽  
Frank Wien ◽  
Jonathan G. Lees ◽  
B.A. Wallace
Keyword(s):  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Secondary Structure ◽  
Optical Rotation ◽  
Good Practice ◽  
Protein Secondary Structure ◽  
Cd Spectroscopy ◽  
Synchrotron Source ◽  
Calibration Methods ◽  
Circular Dichroïsm

Circular dichroism (CD) spectroscopy is an important tool in structural biology, especially for protein secondary structure analyses. Synchrotron radiation circular dichroism (SRCD) spectroscopy is a modified version of the technique that uses the intense light from a synchrotron source to enable the collection of data to much lower wavelengths than possible on conventional circular dichroism (cCD) instruments. There is a need for standardization of calibration methods amongst and between cCD and SRCD instruments to ensure consistency and the ability to use common reference databases for empirical secondary structural analyses. In a previous study (Spectroscopy17(2003), 653–661), we compared optical rotation measurements on several cCD and SRCD instruments, whilst holding constant other experimental factors. In this study, other experimental parameters which contribute to the spectral magnitude, such as cell pathlength and protein concentration determinations, are examined. In addition, the extent of wavelength calibration variations between instruments and their effects on secondary structure calculations have been examined. Hence, this paper provides additional practical guidance for “good practice” in the measurement of CD data.

scholarly journals Investigation by Synchrotron Radiation Circular Dichroism of the Secondary Structure Evolution of Pepsin under Oxidative Environment

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 998
Author(s):  
Laetitia Théron ◽  
Aline Bonifacie ◽  
Jérémy Delabre ◽  
Thierry Sayd ◽  
Laurent Aubry ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Secondary Structure ◽  
Proteolytic Activity ◽  
Digestive Enzyme ◽  
Structure Evolution ◽  
Food Protein ◽  
Maldi Tof ◽  
Kinetics Of ◽  
Circular Dichroïsm

Food processing affects the structure and chemical state of proteins. In particular, protein oxidation occurs and may impair protein properties. These chemical reactions initiated during processing can develop during digestion. Indeed, the physicochemical conditions of the stomach (oxygen pressure, low pH) favor oxidation. In that respect, digestive proteases may be affected as well. Yet, very little is known about the link between endogenous oxidation of digestive enzymes, their potential denaturation, and, therefore, food protein digestibility. Thus, the objective of this study is to understand how oxidative chemical processes will impact the pepsin secondary structure and its hydrolytic activity. The folding and unfolding kinetics of pepsin under oxidative conditions was determined using Synchrotron Radiation Circular Dichroism. SRCD gave us the possibility to monitor the rapid kinetics of protein folding and unfolding in real-time, giving highly resolved spectral data. The proteolytic activity of control and oxidized pepsin was investigated by MALDI-TOF mass spectrometry on a meat protein model, the creatine kinase. MALDI-TOF MS allowed a rapid evaluation of the proteolytic activity through peptide fingerprint. This study opens up new perspectives by shifting the digestion paradigm taking into account the gastric digestive enzyme and its substrate.

Elucidating protein secondary structure with circular dichroism and a neural network

2013 ◽  
Vol 34 (32) ◽  
pp. 2774-2786 ◽  
Author(s):  
Vincent Hall ◽  
Anthony Nash ◽  
Evor Hines ◽  
Alison Rodger
Keyword(s):  
Neural Network ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Protein Secondary Structure ◽  
Circular Dichroïsm
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