Far-ultraviolet circular dichroism of N-acetylglucosamine, glucuronic acid, and hyaluronic acid

1977 ◽  
Vol 99 (6) ◽  
pp. 1730-1734 ◽  
Author(s):  
Lynn A. Buffington ◽  
Eugene S. Pysh ◽  
Bireswar Chakrabarti ◽  
Endre A. Balazs
Keyword(s):  
Hyaluronic Acid ◽  
Circular Dichroism ◽  
Glucuronic Acid ◽  
Far Ultraviolet ◽  
Circular Dichroïsm

Circular dichroism studies of sheep β-lipotropic hormone

1976 ◽  
Vol 54 (11) ◽  
pp. 992-998 ◽  
Author(s):  
Serge St-Pierre ◽  
Claude Gilardeau ◽  
Michel Chrétien
Keyword(s):  
Circular Dichroism ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Conformational Transition ◽  
Acidic Solutions ◽  
Nacl Concentration ◽  
Helical Content ◽  
The Stability ◽  
Far Ultraviolet ◽  
Circular Dichroïsm

The far ultraviolet circular dichroism spectra of sheep β-lipotropic hormone (β-LPH) were recorded under different conditions of pH, temperature, salt concentration, and solvent composition. Results confirm the stability of the hormone in strong basic or acidic solutions; moreover, temperatures up to 50 °C do not seem to affect noticeably the conformation of β-LPH. However, increasing the NaCl concentration or addition of dioxane in the solution brings about a conformational transition of the chain, interpreted as an increase in the helical content. The method of Yang (Chen, Y. H., Yang, J. T. &Martinez, H. M. (1972) Biochemistry 11, 4120–4131) was used to compute the proportion of helical, β, and unordered forms of the hormone chain. The proportions are compared with those obtained from Fasman's predictive method (Chou, P. Y. &Fasman, G. D. (1974) Biochemistry 13, 211–221 and Chou, P. Y. &Fasman, G. D. (1974) Biochemistry 13, 222–245) based on the known amino acid sequence of β-LPH.

Vibronic structure in the far-UV electronic circular dichroism spectra of proteins

2015 ◽  
Vol 177 ◽  
pp. 329-344 ◽  
Author(s):  
Zhuo Li ◽  
David Robinson ◽  
Jonathan D. Hirst
Keyword(s):  
Circular Dichroism ◽  
Matrix Method ◽  
Vibrational Structure ◽  
Cd Spectra ◽  
Peptide Backbone ◽  
Electronic Circular Dichroism ◽  
Vibronic Structure ◽  
Far Ultraviolet ◽  
High Level ◽  
Circular Dichroïsm

The Franck–Condon effect is considered and the vibrational structure of the πnbπ* transition of the peptide backbone is incorporated into matrix method calculations of the electronic circular dichroism (CD) spectra of proteins in the far-ultraviolet. We employ the state-averaged CASPT2 method to calculate the ground and πnbπ* excited state geometries and frequencies of N-methylacetamide (NMA), which represents the peptide chromophore. The results of these calculations are used to incorporate vibronic levels of the excited states into the matrix method calculation. The CD spectra of a set of 49 proteins, comprising a range of structural types, are calculated to assess the influence of the vibrational structure. The calculated spectra of α-helical proteins are better resolved using the vibronic parameters and correlation between the experimental and the calculated intensity of less regular β structure proteins improves over most wavelengths in the far-UV. No obvious improvement is observed in the calculated spectra of regular β-sheet proteins. Our high-level ab initio calculations of the vibronic structure of the πnbπ* transition in NMA have provided some further insight into the physical origins of the nature of protein CD spectra in the far-UV.

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