Axial ligation-induced structural changes in nickel hydrocorphinoids related to coenzyme F430 detected by Raman difference spectroscopy

1987 ◽  
Vol 109 (14) ◽  
pp. 4169-4173 ◽  
Author(s):  
J. A. Shelnutt



1981 ◽  
Author(s):  
German B Villanueva

It is known that storage at pH 6 stabilizes thrombin against inactivation. In order to determine whether structural changes accompany this stabilization, the conformation of human α-thrombin at pH 6.0 and 7.5 was investigated by chemical modification, solvent perturbation, UV difference spectroscopy and circular dichroism. It was shown that the CD spectra of α-thrombin at 230-200 nm peptide region were indistinguishable at two pH values indicating no difference in the secondary structure. However, differences were observed in the 320-250 nm aromatic region suggesting some changes in the microenvironment of the aromatic chromophores. Solvent perturbation in 20% ethylene glycol indicated 3.7 ± 0.5 Trp and 7.8 ± 0.5 Tyr were exposed to the solvent at pH 6.0 while 4.3 ± 0.4 Trp and 8.4 ± 0.5 Tyr were exposed at pH 7.5. Chemical modification of tryptophan residue by dimethyl(2-hydroxy- 5-nitrobenzyl)sulfonium bromide in a 100-fold molar excess of the reagent showed 3 reactive residues at pH 6.0 and 6 at pH 7.5. These results suggest that when thrombin is exposed to low pH, structural changes occur that decrease the relative degree of exposure of tryptophan and tyrosine residues. Furthermore, UV difference spectroscopy showed the development of a positive differential spectrum when thrombin at pH 6.0 was exposed to pH 7.5. From this study, it is concluded that the stability of thrombin at pH 6.0 is due to a more compact structure of the enzyme which is probably a result of reduced charge interaction at low pH.



RSC Advances ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 383-392 ◽  
Author(s):  
Faisal Hammad Mekky Koua ◽  
Hideki Kandori

Fulvimarina pelagirhodopsin (FR) is a member of inward eubacterial light-activated Cl−translocating rhodopsins (ClR) that were found recently in marine bacteria.



2014 ◽  
Vol 16 (27) ◽  
pp. 14220-14230 ◽  
Author(s):  
M. Horch ◽  
A. F. Pinto ◽  
T. Utesch ◽  
M. A. Mroginski ◽  
C. V. Romão ◽  
...  

Local and global structural changes that enable reductive activation of superoxide reductase are revealed by a combined approach of infrared difference spectroscopy and computational methods.



2008 ◽  
Vol 105 (34) ◽  
pp. 12113-12117 ◽  
Author(s):  
X. Jiang ◽  
E. Zaitseva ◽  
M. Schmidt ◽  
F. Siebert ◽  
M. Engelhard ◽  
...  


2016 ◽  
Vol 121 (2) ◽  
pp. 335-350 ◽  
Author(s):  
Tilman Kottke ◽  
Víctor A. Lórenz-Fonfría ◽  
Joachim Heberle


BIO-PROTOCOL ◽  
2021 ◽  
Vol 11 (3) ◽  
Author(s):  
Lukas Goett-Zink ◽  
Jessica Klocke ◽  
Tilman Kottke


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