Role of Threonine 101 on the Stability of the Heme Active Site of Cytochrome P450cam:  Multiwavelength Circular Dichroism Studies†

Biochemistry ◽  
2006 ◽  
Vol 45 (42) ◽  
pp. 12715-12722 ◽  
Author(s):  
Soumen Kanti Manna ◽  
Shyamalava Mazumdar
Keyword(s):  
Circular Dichroism ◽  
Active Site ◽  
Cytochrome P450cam ◽  
The Stability ◽  
Circular Dichroïsm

scholarly journals Viviparus ater Hemocyanin: Investigation of the Dioxygen-Binding Site and Stability of the Oxy- and Apo-Forms

2001 ◽  
Vol 56 (9-10) ◽  
pp. 843-847
Author(s):  
Dessislava Nikolova Georgieva ◽  
Stanka Stoeva ◽  
Wolfgang Voelter ◽  
Nicolay Genov
Keyword(s):  
Binding Site ◽  
Charge Distribution ◽  
Active Site ◽  
Binding Sites ◽  
Binuclear Copper ◽  
Circular Dichroism Spectra ◽  
Melting Temperatures ◽  
The Stability ◽  
Circular Dichroïsm

Abstract The active site of Viviparus ater (mollusc) hemocyanin was investigated using the fact that the binding of dioxygen to the binuclear copper-containing sites of hemocyanins is connected with the appearance of specific dichroic bands which are very sensitive to changes in the structrure and polarity of the environment. Oxy-Viviparus ater hemocyanin exhibits near UV and visible circular dichroism spectra different from those of other molluscan and arthropo-dan hemocyanins. These differences are due probably to variations in the geometry or charge distribution in the dioxygen binding sites of the compared proteins.The thermostability of Viviparus ater hemocyanin and the significance of the copper-dioxy-gen system for the stability were also investigated. “Melting” temperatures, Tm, of 77 °C for the oxy-hemocyanin and 57 °C for the apo-protein were calculated from the denaturation curves which demonstrates the considerable role of the binuclear active site for the thermostability. Viviparus ater hemocyanin is more thermostable than other hemocyanins for which data are published.

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

A β-cyclodextrin–resveratrol inclusion complex and the role of geometrical and electronic effects on its electronic induced circular dichroism

RSC Advances ◽  
2013 ◽  
Vol 3 (26) ◽  
pp. 10242 ◽  
Author(s):  
Eduardo Troche-Pesqueira ◽  
Ignacio Pérez-Juste ◽  
Armando Navarro-Vázquez ◽  
María Magdalena Cid
Keyword(s):  
Circular Dichroism ◽  
Inclusion Complex ◽  
Induced Circular Dichroism ◽  
Electronic Effects ◽  
Circular Dichroïsm

The important role of non-covalent interactions for the vibrational circular dichroism of lactic acid in aqueous solution

2021 ◽  
Author(s):  
Sascha Jähnigen ◽  
Daniel Sebastiani ◽  
Rodolphe Vuilleumier
Keyword(s):  
Lactic Acid ◽  
Circular Dichroism ◽  
Computational Study ◽  
Bulk Water ◽  
Vibrational Circular Dichroism ◽  
Ab Initio Molecular Dynamics ◽  
Non Covalent Interactions ◽  
Circular Dichroïsm ◽  
Covalent Interactions

We present a computational study of vibrational circular dichroism (VCD) in solutions of (S)-lactic acid, relying on ab initio molecular dynamics (AIMD) and full solvation with bulk water. We discuss...

Citrate chelation as a potential mechanism against aluminum toxicity in cells: the role of calmodulin

1985 ◽  
Vol 63 (11) ◽  
pp. 1167-1175 ◽  
Author(s):  
Charles G. Suhayda ◽  
Alfred Haug
Keyword(s):  
Circular Dichroism ◽  
Conceptual Understanding ◽  
Aluminum Toxicity ◽  
Hydrophobic Surface ◽  
Native Structure ◽  
Calcium Calmodulin Dependent ◽  
Α Helix ◽  
Kinetics Of ◽  
Circular Dichroïsm

At a molar excess of [citrate]/[aluminum], this organic acid can protect calmodulin from aluminum binding if the metal is presented to the protein in stoichiometric micromolar quantities, as judged by fluorescence and circular dichroism spectroscopy. Similar citrate concentrations are also capable of fully restoring calmodulin's hydrophobic surface exposure to that of the native protein when calmodulin was initially damaged by aluminum binding. Fluoride anions are equally effective in restoring calmodulin's native structure as determined by fluorescence spectroscopy. Measurements of the kinetics of citrate-mediated aluminum removal also indicated that the metal ions are completely removed from calmodulin, consistent with results derived from atomic absorption experiments. On the other hand, results from circular dichroism studies indicated that citrate-mediated aluminum removal from calmodulin can only partially restore the α-helix content to that originally present in apocalmodulin or in calcium–calmodulin, dependent upon the absence or presence of calcium ions. The results that chelators like citrate can protect calmodulin from aluminum injury may provide a conceptual understanding of physiological observations regarding aluminum-tolerant plant species which are generally rich in certain organic acids.

Critical Role of Capping Layer in Determining Co−Fe−B/MgO Interfacial Magnetism Revealed by X-Ray Magnetic Circular Dichroism

2020 ◽  
Vol 14 (5) ◽  
Author(s):  
James Lourembam ◽  
Xiaojiang Yu ◽  
Maria Patricia Rouelli Sabino ◽  
Michael Tran ◽  
Roslyn Wan Teng Ang ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Critical Role ◽  
Capping Layer ◽  
X Ray ◽  
Circular Dichroïsm

Circular dichroism studies of sheep β-lipotropic hormone

1976 ◽  
Vol 54 (11) ◽  
pp. 992-998 ◽  
Author(s):  
Serge St-Pierre ◽  
Claude Gilardeau ◽  
Michel Chrétien
Keyword(s):  
Circular Dichroism ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Conformational Transition ◽  
Acidic Solutions ◽  
Nacl Concentration ◽  
Helical Content ◽  
The Stability ◽  
Far Ultraviolet ◽  
Circular Dichroïsm

The far ultraviolet circular dichroism spectra of sheep β-lipotropic hormone (β-LPH) were recorded under different conditions of pH, temperature, salt concentration, and solvent composition. Results confirm the stability of the hormone in strong basic or acidic solutions; moreover, temperatures up to 50 °C do not seem to affect noticeably the conformation of β-LPH. However, increasing the NaCl concentration or addition of dioxane in the solution brings about a conformational transition of the chain, interpreted as an increase in the helical content. The method of Yang (Chen, Y. H., Yang, J. T. &Martinez, H. M. (1972) Biochemistry 11, 4120–4131) was used to compute the proportion of helical, β, and unordered forms of the hormone chain. The proportions are compared with those obtained from Fasman's predictive method (Chou, P. Y. &Fasman, G. D. (1974) Biochemistry 13, 211–221 and Chou, P. Y. &Fasman, G. D. (1974) Biochemistry 13, 222–245) based on the known amino acid sequence of β-LPH.

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