scholarly journals Multispectroscopic Study of the Interaction of Chloramphenicol with Human Neuroglobin

2012 ◽  
Vol 27 ◽  
pp. 143-154 ◽  
Author(s):  
Lei Huang ◽  
Lianzhi Li ◽  
Haili Li ◽  
Chaohui Gao ◽  
Hui Cui ◽  
...  
Keyword(s):  
Fluorescence Spectra ◽  
Entropy Change ◽  
Cd Spectroscopy ◽  
Synchronous Fluorescence ◽  
Cd Spectra ◽  
Tyrosine Residues ◽  
Synchronous Fluorescence Spectra ◽  
Quenching Efficiency ◽  
Tryptophan Residues ◽  
Α Helix

The interaction between chloramphenicol (CHL) and neuroglobin (Ngb) has been investigated by using fluorescence, synchronous fluorescence, UV-Vis and circular dichroism (CD) spectroscopy. It has been found that CHL molecule can quench the intrinsic fluorescence of Ngb in a way of dynamic quenching mechanism, which was supported by UV-Vis spectral data. Their effective quenching constants (KSV) are2.2×104,2.6×104,and 3.1×104 L⋅mol−1at 298 K, 303 K, and 308 K, respectively. The enthalpy change (ΔH) and entropy change (ΔS) for this reaction are 26.42 kJ⋅mol−1and 171.7 J⋅K−1, respectively. It means that the hydrophobic interaction is the main intermolecular force of the interaction between CHL and Ngb. Synchronous fluorescence spectra showed that the microenvironment of tryptophan and tyrosine residues of Ngb has been changed slightly. The fluorescence quenching efficiency of CHL to tyrosine residues is a little bit more than that to tryptophan residues of Ngb. Furthermore, CD spectra indicated that CHL can induce the formation of α-helix of Ngb.

scholarly journals BeStSel: From Secondary Structure Analysis to Protein Fold Prediction by Circular Dichroism Spectroscopy

2020 ◽  
pp. 175-189
Author(s):  
András Micsonai ◽  
Éva Bulyáki ◽  
József Kardos
Keyword(s):  
Circular Dichroism ◽  
Secondary Structure ◽  
Classical Method ◽  
Cd Spectroscopy ◽  
Protein Fold ◽  
Cd Spectra ◽  
Secondary Structure Analysis ◽  
Β Sheets ◽  
Α Helix ◽  
Circular Dichroïsm

Abstract Far-UV circular dichroism (CD) spectroscopy is a classical method for the study of the secondary structure of polypeptides in solution. It has been the general view that the α-helix content can be estimated accurately from the CD spectra. However, the technique was less reliable to estimate the β-sheet contents as a consequence of the structural variety of the β-sheets, which is reflected in a large spectral diversity of the CD spectra of proteins containing this secondary structure component. By taking into account the parallel or antiparallel orientation and the twist of the β-sheets, the Beta Structure Selection (BeStSel) method provides an improved β-structure determination and its performance is more accurate for any of the secondary structure types compared to previous CD spectrum analysis algorithms. Moreover, BeStSel provides extra information on the orientation and twist of the β-sheets which is sufficient for the prediction of the protein fold. The advantage of CD spectroscopy is that it is a fast and inexpensive technique with easy data processing which can be used in a wide protein concentration range and under various buffer conditions. It is especially useful when the atomic resolution structure is not available, such as the case of protein aggregates, membrane proteins or natively disordered chains, for studying conformational transitions, testing the effect of the environmental conditions on the protein structure, for verifying the correct fold of recombinant proteins in every scientific fields working on proteins from basic protein science to biotechnology and pharmaceutical industry. Here, we provide a brief step-by-step guide to record the CD spectra of proteins and their analysis with the BeStSel method.

The synchronous fluorescence spectra character of hypocrellin B with type I collagen under irradiation

2014 ◽  
Author(s):  
Jucheng Zhang ◽  
Heping Yan ◽  
Mengting Yang ◽  
Yongzhen Feng ◽  
Yun Huang ◽  
...  
Keyword(s):  
Fluorescence Spectra ◽  
Type I Collagen ◽  
Synchronous Fluorescence ◽  
Type I ◽  
Synchronous Fluorescence Spectra ◽  
Hypocrellin B

scholarly journals Synchronous fluorescence spectra of water contaminated by dispersed crude oil

2020 ◽  
Vol 50 (1) ◽  
Author(s):  
Emilia Baszanowska ◽  
Zbigniew Otremba
Keyword(s):  
Crude Oil ◽  
Fluorescence Spectra ◽  
Oil Pollution ◽  
Synchronous Fluorescence ◽  
Mining Equipment ◽  
Oil Emulsion ◽  
Synchronous Fluorescence Spectra ◽  
Emulsion Concentration ◽  
Petroleum Extraction

The development of petroleum extraction and transport technology does not ensure complete isolation of these substances from the natural environment. This problem is exacerbated by the location of mining equipment on the sea shelf and the fact that numerous submarine pipelines, tankers and handling terminals can also emit oil pollution. Therefore, the possibility of detecting oil dispersed in the water is particularly important. This paper reports the efforts to identify methods of characterization of the water containing the crude oil emulsion in a very low concentration (a few to several tens of ppm). Due to this, the effect of emulsion concentration on the possibility of its objective characterization using synchronous fluorescence spectra was studied. The similarity of spectra at various oil concentrations was analysed. It has been shown that the stabilization of the shape of synchronous fluorescence spectra occurs at relatively low oil concentrations.

Using fluorescence quenching combined with two-dimensional correlation fluorescence spectroscopy to characterise the binding-site heterogeneity of dissolved organic matter with copper and mercury in lake sediments

2017 ◽  
Vol 14 (2) ◽  
pp. 91 ◽  
Author(s):  
Xu-jing Guo ◽  
Yun-zhen Li ◽  
Yan-hong Feng ◽  
Dong-hai Yuan
Keyword(s):  
Organic Matter ◽  
Fluorescence Quenching ◽  
Binding Site ◽  
Fluorescence Spectra ◽  
Correlation Spectroscopy ◽  
Synchronous Fluorescence ◽  
Two Dimensional ◽  
Synchronous Fluorescence Spectra ◽  
Site Heterogeneity ◽  
Different Sources

Environmental contextDissolved organic matter (DOM) plays an important role in influencing the migration and ultimate fate of metals. Different sources of pollution resulted in changes in the structure of sediment DOM in Lake Wuliangsuhai. We investigate the binding properties of DOM with CuII and HgII using fluorescence quenching combined with two-dimensional correlation spectroscopy (2D-COS) in order to demonstrate the influence of different sources of DOM on metals. AbstractDissolved organic matter (DOM) was collected from three sampling sites (L1, L2 and L3) in Lake Wuliangsuhai. L1 received upstream industrial wastewater and domestic sewage. L2 had suffered from agricultural non-point source pollution. L3 was situated in the lake outlet area. The complexation of DOM with CuII and HgII was investigated based on fluorescence quenching of the synchronous fluorescence spectra on the addition of CuII and on two-dimensional correlation spectroscopy (2D-COS). The synchronous and asynchronous maps derived from 2D-COS provided a clear picture of the heterogeneous distribution of CuII and HgII binding sites, which was not readily detected using only the synchronous fluorescence spectra. CuII and HgII complexation was stronger at shorter wavelengths than at longer wavelengths. Moreover, fluorescence quenching also occurred intensely in the fulvic-like regions (363nm for DOM-Cu in L2 and 365nm for DOM-Hg in L1). The logarithms of the stability constants (log KM) ranged from 4.42 to 6.23, from 4.75 to 4.86, and from 4.80 to 5.73 for DOM-Cu in L1, L2 and L3, respectively, depending on the wavelength. DOM at the longer wavelengths exhibited a higher log KM than that at the shorter wavelengths, and the f values in the protein-like region were clearly high. These results suggest that the influence of the structural and chemical properties of DOM on CuII binding may differ for DOM from different sources. The combined approach of fluorescence quenching and 2D-COS could be applied as a tool for evaluating the metal binding site heterogeneity of DOM.

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