Effects of guanidine hydrochloride on the conformation and enzyme activity of streptomycin adenylyltransferase monitored by circular dichroism and fluorescence spectroscopy

2006 ◽  
Vol 71 (11) ◽  
pp. 1230-1237 ◽  
Author(s):  
Snehasis Jana ◽  
Tapan Kumar Chaudhuri ◽  
J. K. Deb
Keyword(s):  
Enzyme Activity ◽  
Circular Dichroism ◽  
Fluorescence Spectroscopy ◽  
Guanidine Hydrochloride ◽  
Circular Dichroïsm

scholarly journals Folding mechanism of canine milk lysozyme studied by circular dichroism and fluorescence spectroscopy

2003 ◽  
Vol 17 (2-3) ◽  
pp. 183-193 ◽  
Author(s):  
Masaharu Nakao ◽  
Munehito Arai ◽  
Takumi Koshiba ◽  
Katsutoshi Nitta ◽  
Kunihiro Kuwajima
Keyword(s):  
Circular Dichroism ◽  
Fluorescence Spectroscopy ◽  
Molten Globule ◽  
Guanidine Hydrochloride ◽  
Folding Intermediates ◽  
Equilibrium Unfolding ◽  
Burst Phase ◽  
The Relationship ◽  
Kinetics Of ◽  
Circular Dichroïsm

We have studied the guanidine hydrochloride‒induced equilibrium unfolding and the kinetics of refolding of canine milk lysozyme by circular dichroism and fluorescence spectroscopy. The thermodynamic analysis of the equilibrium unfolding measured by circular dichroism and fluorescence has shown that unfolding is represented by a three‒state mechanism and that the intermediate state of canine milk lysozyme is remarkably more stable than the intermediates observed in other lysozyme and α-lactalbumin. In the kinetic refolding of this protein, there are at least two kinetic intermediates; a burst=phase intermediate accumulated within the dead time (4 ms) of the measurement and an intermediate that has been observed during the kinetics with a rate constant of 10–20 s–1after the burst phase. This result is apparently in contrast with those previously observed in the kinetic refolding of α‒lactalbumin and equine lysozyme that show only the burst‒phase intermediate. The relationship between the extraordinarily stable equilibrium molten globule and the kinetic folding intermediates will be discussed.

Structural Differences of Ovalbumin and S-Ovalbumin Revealed by Denaturing Conditions

1997 ◽  
Vol 52 (9-10) ◽  
pp. 645-653 ◽  
Author(s):  
Corrado Paolinelli ◽  
Mario Barteri ◽  
Federico Boffi ◽  
Francesca Forastieri ◽  
Maria Cristina Gaudiano ◽  
...  
Keyword(s):  
Experimental Data ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Guanidine Hydrochloride ◽  
Stable Form ◽  
X Ray ◽  
Heat Stable ◽  
X Ray Scattering ◽  
Structural Differences ◽  
Circular Dichroïsm

We found, by circular dichroism and Raman spectroscopy measurements, that the secondary structure of the native ovalbumin and of its heat-stable form, called S-ovalbumin, is a probe of the structural differences between the two proteins. Small angle X-ray scattering and circular dichroism measurements performed on the two proteins under denaturing conditions, with different concentrations of guanidine hydrochloride, show the changes of the tertiary and secondary structure and a different pathway in the unfolding process. These experimental data confirm that the conversion of native ovalbumin into S-ovalbumin is irreversible and reveal that the response of the two proteins to the same chemical environment is different

Spectroscopic and biophysical approaches for studying the structure and function of the P-glycoprotein multidrug transporter

1998 ◽  
Vol 76 (5) ◽  
pp. 695-708 ◽  
Author(s):  
Frances J Sharom ◽  
Ronghua Liu ◽  
Yolanda Romsicki
Keyword(s):  
Electron Microscopy ◽  
Circular Dichroism ◽  
Multidrug Resistance ◽  
Fluorescence Spectroscopy ◽  
Lipid Bilayers ◽  
Drug Transport ◽  
Circular Dichroism Spectroscopy ◽  
P Glycoprotein ◽  
Infra Red ◽  
Circular Dichroïsm

Multidrug resistance is a serious obstacle to the successful chemotherapeutic treatment of many human cancers. A major cause of multidrug resistance is the overexpression of a 170-kDa plasma membrane protein, known as P-glycoprotein, which appears to function as an ATP-driven efflux pump with a very broad specificity for hydrophobic drugs, peptides, and natural products. P-Glycoprotein is a member of the ABC superfamily and is proposed to consist of two homologous halves, each comprising six membrane-spanning segments and a cytosolic nucleotide binding domain. In recent years, P-glycoprotein has been purified and functionally reconstituted into lipid bilayers, where it retains both ATPase and drug transport activity. The availability of purified active protein has led to substantial advances in our understanding of the molecular structure and mechanism of action of this unique transporter. This review will focus on the recent application of fluorescence spectroscopy, infra-red spectroscopy, circular dichroism spectroscopy, electron microscopy, and other biophysical techniques to the study of P-glycoprotein structure and function.Key words: multidrug resistance, P-glycoprotein, fluorescence spectroscopy, infra-red spectroscopy, circular dichroism spectroscopy, differential scanning calorimetry, electron microscopy.

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