scholarly journals Biological Activities and Structural Properties of the Atypical Bacteriocins Mesenterocin 52B and Leucocin B-TA33a

2001 ◽  
Vol 67 (4) ◽  
pp. 1418-1422 ◽  
Author(s):  
C. Corbier ◽  
F. Krier ◽  
G. Mulliert ◽  
B. Vitoux ◽  
A.-M. Revol-Junelles
Keyword(s):  
Circular Dichroism ◽  
Structural Properties ◽  
Sequence Homology ◽  
Synthetic Peptides ◽  
Biological Activities ◽  
Modes Of Action ◽  
Amphiphilic Helix ◽  
High Sequence Homology ◽  
Circular Dichroïsm

ABSTRACT The antibacterial spectra and modes of action of synthetic peptides corresponding to mesenterocin 52B and leucocin B-TA33a greatly differ despite their high sequence homology. Circular dichroism experiments establish the capacity of each of these two peptides to partly fold into an amphiphilic helix that might be crucial for their adsorption at lipophilic-hydrophilic interfaces.

scholarly journals A Raman, SERS and UV-circular dichroism spectroscopic study of N-acetyl-l-cysteine in aqueous solutions

2019 ◽  
Vol 43 (38) ◽  
pp. 15201-15212 ◽  
Author(s):  
R. A. Cobos Picot ◽  
M. Puiatti ◽  
A. Ben Altabef ◽  
R. J. G. Rubira ◽  
S. Sanchez-Cortes ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Circular Dichroism ◽  
Aqueous Solutions ◽  
Spectroscopic Study ◽  
Electronic Properties ◽  
Structural Properties ◽  
Amine Groups ◽  
Circular Dichroïsm

The aim of this work is to evaluate the vibrational and structural properties of N-acetyl-l-cysteine (NAC), and its molecular structure and electronic properties in relation to the action of thiol and amine groups at different pH.

Conformational Analysis of Diterpene Lactone Andrographolide towards Reestablishment of Its Absolute Configuration via Theoretical and Experimental ECD and VCD Methods

2020 ◽  
Vol 21 (1) ◽  
pp. 148
Author(s):  
Muhamad Faid A Kadir ◽  
Agustono Wibowo ◽  
Fatimah Salim ◽  
El Hassane Anouar ◽  
Khalijah Awang ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Conformational Analysis ◽  
Absolute Configuration ◽  
Theoretical Calculations ◽  
Biological Activities ◽  
Docking Studies ◽  
Basis Set ◽  
Major Constituent ◽  
Dft Methods ◽  
Circular Dichroïsm

Andrographolide, the major constituent from the terrestrial plant Andrographis paniculata is a much-studied bioactive ent-labdane diterpene lactone and has become an important medicinal intermediate. Its structure as determined by X-ray crystallography has been applied in molecular docking studies to explain biological activities. Nevertheless, recently there has been a number of conflicting reports concerning the stereochemistry at the C-14 and C-10 positions affecting the absolute configuration (AC) of the compound. Since a lack of information on the molecular flexibility of the molecule can lead to misleading conclusions on biological activity, a conformational analysis of the molecule in the solution state was necessary. The conformational analysis was performed by the Spartan14 package using the Merck Molecular Force Field (MMFF). The exciton chirality method in electronic circular dichroism spectroscopy (ECM-ECD) and vibrational circular dichroism (VCD) techniques were then jointly employed to re-establish the AC of andrographolide. Theoretical calculations were performed using TD-DFT methods by using the hybrid functionals B3LYP and CAM-B3LYP combined with 6-31G(d,p) basis set. Long-range exciton coupling of 2-naphthoyl chromophores at C-14 and C-19 led to the establishment of the AC to be 3R, 4R, 5S, 9R, 10R and 14S. Comparison between the theoretical VCD data of 14-S and 14-R stereoisomer confirmed a configuration of S at C-14 position instead of R.

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