Changes in the circular dichroic spectrum of colchicine associated with its binding to tubulin

Biochemistry ◽  
1981 ◽  
Vol 20 (21) ◽  
pp. 5999-6005 ◽  
Author(s):  
H. William Detrich ◽  
Robley C. Williams ◽  
Timothy L. Macdonald ◽  
Leslie Wilson ◽  
David Puett
Keyword(s):  
Circular Dichroic Spectrum ◽  
Circular Dichroic

Linear oligopeptides. XXVII. Contribution to the circular dichroism of internal peptide chromophores

1976 ◽  
Vol 54 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Claudio Toniolo ◽  
Gian Maria Bonora
Keyword(s):  
Circular Dichroism ◽  
Solvent Polarity ◽  
Guanidinium Chloride ◽  
Negative Band ◽  
Circular Dichroic Spectrum ◽  
Internal Peptide ◽  
Circular Dichroïsm ◽  
Sulfur Containing ◽  
Circular Dichroic ◽  
Molar Ellipticity

The contribution to the circular dichroism of L-Ala-L-Ala, L-Nva-L-Nva, L-Val-L-Val, L-Leu-L-Leu, L-Ile-L-Ile, L-Cys(Me)-L-Cys(Me), L-Met-L-Met, and L-Phe-L-Phe internal peptide chromophores in 1,1,1,3,3,3-hexafluoropropan-2-ol were calculated by subtracting the total molar ellipticity values of N- and C-protected homo-trimers from those of the pertinent protected homo-tetramers.The circular dichroism of the internal peptide chromophore of aliphatic hydrocarbon- and sulfur-containing peptides, each of the L-configuration, show a negative band at 2l5–230 nm accompanied by a more intense negative band near 200 nm. A structured weak and negative band near 260 nm along with bands at 240 nm (negative), 222 nm (positive), and 210.5 nm (negative) of progressively increasing intensity are apparent in the circular dichroic spectrum of L-Phe-L-Phe internal peptide chromophore. The effect of solvent polarity is discussed in the case of L-Val-L-Val and L-Ala-L-Ala internal peptide chromophores.Among the protected homo-trimers and tetramers only those of L-alanine are soluble in aqueous solution; consequently, the effect of water as a function of temperature, urea, and guanidinium chloride on the L-Ala-L-Ala internal peptide chromophore circular dichroism was established.

scholarly journals The nature of the circular-dichoric spectra of complexes between ribonuclease A and nucleotides

1977 ◽  
Vol 167 (3) ◽  
pp. 749-757 ◽  
Author(s):  
S M Dudkin ◽  
L V Karabashyan ◽  
M Y Karpeisky ◽  
S N Mikhailov ◽  
N S Padyukova ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Ribonuclease A ◽  
Circular Dichroic Spectrum ◽  
Nucleotide Conformation ◽  
Anti Conformation ◽  
Two Factors ◽  
Wavelength Absorption ◽  
Comparison Of The Results ◽  
Circular Dichroïsm ◽  
Circular Dichroic

The circular-dichroism and proton-magnetic-resonance spectra of complexes of ribonuclease A with dihydrouridine 3′-phosphate, 2′- and 3′-CMP, arabinosyl-3′-CMP, 1-(2-hydroxyethyl)cytosine 2′-phosphate and 1-(3-hydroxypropyl)cytosine 3′-phosphate were studied. Comparison of the results shows that non-additivity of the circular-dichroic spectrum of an enzyme-nucleotide complex may be due to: (a), alteration of the circular dichroic spectrum of the nucleotide under the influence of the asymmetric protein matrix (induced dichroism), and (b) a change in the nucleotide conformation. The contribution of each of the two factors was estimated to calculate the circular-dichoroic spectra of 2′-CMP and 3′-CMP in complex with ribonuclease A. 3′-CMP in this complex was characterized by negative circular dichroism in the long-wavelength absorption band of the nucleotide, whereas 2′-CMP was characterized by positive circular dichroism. Since both nucleotides in the complex are known to be in an anti conformation, it follows that even small changes in the conformation considerably modify the circular-dichroic spectrum of the nucleotide in complex with the enzyme.

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