scholarly journals Bacterial Luciferases from Vibrio harveyi and Photobacterium leiognathi Demonstrate Different Conformational Stability as Detected by Time-Resolved Fluorescence Spectroscopy

2021 ◽  
Vol 22 (19) ◽  
pp. 10449
Author(s):  
Elena V. Nemtseva ◽  
Dmitry V. Gulnov ◽  
Marina A. Gerasimova ◽  
Lev A. Sukovatyi ◽  
Ludmila P. Burakova ◽  
...  

Detecting the folding/unfolding pathways of biological macromolecules is one of the urgent problems of molecular biophysics. The unfolding of bacterial luciferase from Vibrio harveyi is well-studied, unlike that of Photobacterium leiognathi, despite the fact that both of them are actively used as a reporter system. The aim of this study was to compare the conformational transitions of these luciferases from two different protein subfamilies during equilibrium unfolding with urea. Intrinsic steady-state and time-resolved fluorescence spectra and circular dichroism spectra were used to determine the stages of the protein unfolding. Molecular dynamics methods were applied to find the differences in the surroundings of tryptophans in both luciferases. We found that the unfolding pathway is the same for the studied luciferases. However, the results obtained indicate more stable tertiary and secondary structures of P. leiognathi luciferase as compared to enzyme from V. harveyi during the last stage of denaturation, including the unfolding of individual subunits. The distinctions in fluorescence of the two proteins are associated with differences in the structure of the C-terminal domain of α-subunits, which causes different quenching of tryptophan emissions. The time-resolved fluorescence technique proved to be a more effective method for studying protein unfolding than steady-state methods.

The Analyst ◽  
2017 ◽  
Vol 142 (11) ◽  
pp. 1953-1961 ◽  
Author(s):  
Md Arafat Hossain ◽  
John Canning ◽  
Zhikang Yu ◽  
Sandra Ast ◽  
Peter J. Rutledge ◽  
...  

A smartphone fluorimeter is demonstrated for steady-state and time-resolved fluorescence intensity measurements at tunable temperatures.


1985 ◽  
Vol 240 (2) ◽  
pp. 781-791 ◽  
Author(s):  
E.A. Permyakov ◽  
A.V. Ostrovsky ◽  
E.A. Burstein ◽  
P.G. Pleshanov ◽  
Ch. Gerday

2010 ◽  
Vol 8 (3) ◽  
pp. 674-686 ◽  
Author(s):  
Magda Milewska ◽  
Katarzyna Guzow ◽  
Wiesław Wiczk

AbstractThe ability of new chelate ligands, benzoxazol-5-yl-alanine derivatives substituted in position 2 by heteroaromatic substituent, to form complexes with selected metal ions in acetonitrile are studied by means of absorption and steady-state and time-resolved fluorescence spectroscopy. Among the ligands studied, only azaaromatic derivatives form stable complexes with transition metal ions in the ground state. Their absorption bands are bathochromically shifted enabling to use those ligands as ratiometric sensors. The fluorescence of each ligand is quenched by metal ions, however, in the presence of Cd(II) and Zn(II) ions a new red shifted emission band is observed.


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