scholarly journals Nonspecific shielding of unfavorable electrostatic intramolecular interactions in the erythropoietin native-state increase conformational stability and limit non-native aggregation

2015 ◽  
Vol 24 (5) ◽  
pp. 803-811 ◽  
Author(s):  
Douglas D. Banks
Keyword(s):  
Conformational Stability ◽  
Intramolecular Interactions ◽  
Native State ◽  
State Increase

scholarly journals General Counteraction Exerted by Sugars against Denaturants

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 652
Author(s):  
Serena Cozzolino ◽  
Attila Tortorella ◽  
Pompea Del Vecchio ◽  
Giuseppe Graziano
Keyword(s):  
Pure Water ◽  
Conformational Stability ◽  
Sodium Perchlorate ◽  
Accessible Surface Area ◽  
Volume Effect ◽  
Solvent Accessible Surface Area ◽  
Excluded Volume ◽  
Native State ◽  
Stabilizing Agents ◽  
Excluded Volume Effect

The conformational stability of globular proteins is strongly influenced by the addition to water of different co-solutes. Some of the latter destabilize the native state, while others stabilize it. It is emerging that stabilizing agents are able to counteract the action of destabilizing agents. We have already provided experimental evidence that this counteraction is a general phenomenon and offered a rationalization. In the present work, we show that four different sugars, namely fructose, glucose, sucrose, and trehalose, counteract the effect of urea, tetramethylurea, sodium perchlorate, guanidinium chloride, and guanidinium thiocyanate despite the chemical and structural differences of those destabilizing agents. The rationalization we provide is as follows: (a) the solvent-excluded volume effect, a purely entropic effect, stabilizes the native state, whose solvent-accessible surface area is smaller than the one of denatured conformations; (b) the magnitude of the solvent-excluded volume effect increases markedly in ternary solutions because the experimental density of such solutions is larger than that of pure water.

scholarly journals Infrared Spectrum and UV-Induced Photochemistry of Matrix-Isolated Phenyl 1-Hydroxy-2-Naphthoate

Photochem ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 10-25
Author(s):  
İsa Sıdır ◽  
Sándor Góbi ◽  
Yadigar Gülseven Sıdır ◽  
Rui Fausto
Keyword(s):  
Infrared Spectroscopy ◽  
Infrared Spectrum ◽  
Uv Light ◽  
Conformational Stability ◽  
Ester Group ◽  
Intramolecular Interactions ◽  
Excitation Wavelength ◽  
Stable Form ◽  
Stable Conformer ◽  
Conformational Composition

The conformational stability, infrared spectrum, and photochemistry of phenyl 1-hydroxy-2-naphthoate (PHN) were studied by matrix isolation infrared spectroscopy and theoretical computations performed at the DFT(B3LYP)/6-311++G(d,p) level of theory. The main intramolecular interactions determining the relative stability of seven conformers of the molecule were evaluated. According to the calculations, the twofold degenerated O–H···O=C intramolecularly hydrogen-bonded conformer with the phenyl ring ester group ±68.8° out of the plane of the substituted naphtyl moiety is the most stable conformer of the molecule. This conformer is considerably more stable than the second most stable form (by ~15 kJ mol−1), in which a weaker O–H···O–C intramolecular hydrogen bond exists. The compound was isolated in cryogenic argon and N2 matrices, and the conformational composition in the matrices was investigated by infrared spectroscopy. In agreement with the predicted relative energies of the conformers, the analysis of the spectra indicated that only the most stable conformer of PHN was present in the as-deposited matrices. The matrices were then irradiated at various wavelengths by narrowband tunable UV light within the 331.7–235.0 nm wavelength range. This resulted in the photodecarbonylation of PHN, yielding 2-phenoxynaphthalen-1-ol, together with CO. The extension of the decarbonylation was found to depend on the excitation wavelength.

scholarly journals Thermally Stimulated Depolarization Currents (TSDC): A sensitive technique for analyzing protein structure

2010 ◽  
Vol 24 (3-4) ◽  
pp. 297-301 ◽  
Author(s):  
R. Bedotti ◽  
M. G. Bridelli ◽  
R. Capelletti ◽  
E. Polverini
Keyword(s):  
Serum Albumin ◽  
Conformational Stability ◽  
Solvation Shell ◽  
Water Molecules ◽  
Water Mixture ◽  
Native State ◽  
Order Degree ◽  
Vapor Activity ◽  
And Control ◽  
Thermally Stimulated Depolarization

The water molecules surrounding proteins as a thin layer and those packaged in pockets and cavities shape and control their structure. Thermally Stimulated Depolarization Currents (TSDC) technique has been applied to investigate the hydration structure of six proteins with different structural motifs: pepsin,β-lactoglobulin,α-chymotrypsin, bovine serum albumin, human serum albumin and myoglobin, at very low hydration level (water vapor activity aw≈0.80) both in the native state and after treatment in trifluoroethanol/water mixture 80% (v/v). A combined approach based on the use of the TSDC technique, able to distinguish H2O dipoles belonging to the solvation shell in terms of their order degree and mobility, and of FTIR and CD spectroscopies has allowed us to reexamine the problem of conformational stability of macromolecules as a function of their hydration.

scholarly journals Conformational impact of structural modifications in 2-fluorocyclohexanone

2017 ◽  
Vol 13 ◽  
pp. 1781-1787 ◽  
Author(s):  
Francisco A Martins ◽  
Josué M Silla ◽  
Matheus P Freitas
Keyword(s):  
Structural Changes ◽  
Conformational Equilibrium ◽  
Chemical Shifts ◽  
Conformational Stability ◽  
Three Dimensional ◽  
Building Blocks ◽  
Intramolecular Interactions ◽  
Coupling Constants ◽  
Structural Modifications ◽  
Gauche Effect

2-Haloketones are building blocks that combine physical, chemical and biological features of materials and bioactive compounds, while organic fluorine plays a fundamental role in the design of performance organic molecules. Since these features are dependent on the three-dimensional chemical structure of a molecule, simple structural modifications can affect its conformational stability and, consequently, the corresponding physicochemical/biological property of interest. In this work, structural changes in 2-fluorocyclohexanone were theoretically studied with the aim at finding intramolecular interactions that induce the conformational equilibrium towards the axial or equatorial conformer. The interactions evaluated were hydrogen bonding, hyperconjugation, electrostatic and steric effects. While the gauche effect, originated from hyperconjugative interactions, does not appear to cause some preferences for the axial conformation of organofluorine heterocycles, more classical effects indeed rule the conformational equilibrium of the compounds. Spectroscopic parameters (NMR chemical shifts and coupling constants), which can be useful to determine the stereochemistry and the interactions operating in the series of 2-fluorocyclohexanone derivatives, were also calculated.

Residue-wise conformational stability of DLC8 dimer from native-state hydrogen exchange

2008 ◽  
Vol 75 (1) ◽  
pp. 40-52 ◽  
Author(s):  
P. M. Krishna Mohan ◽  
Swagata Chakraborty ◽  
Ramakrishna V. Hosur
Keyword(s):  
Hydrogen Exchange ◽  
Conformational Stability ◽  
Native State

Existence of DNA in yeast microbodies

1978 ◽  
Vol 36 (2) ◽  
pp. 232-233
Author(s):  
Masako Osumi ◽  
Misuzu Nagano ◽  
Hiroko Kazama
Keyword(s):  
Catalase Activity ◽  
Buoyant Density ◽  
Model System ◽  
Contour Length ◽  
Native State ◽  
Normal Alkane ◽  
Remarkable Increase ◽  
Dna Molecule ◽  
Mitochondrial Dnas

We have found that microbodies appeared profusely together with a remarkable increase in catalase activity in normal alkane-grown cells of hydrocarbon-utilizing Candida yeasts, and that the microbodies multiplied by division in these cells. These features of Candida yeasts seem to provide a useful model system for studies on the biogenesis of the microbody. Subsequently, we have succeeded in isolation of Candida microbodies in an apparently native state, as judged biochemically and morphologically. The presence of DNA in the purified microbody fraction thus obtained was proved by the diphenylamine method. DNA molecule of about 15 urn in contour length was released from an isolated microbody. The physicochemical analyses of the microbody DNA revealed that its buoyant density differed from nuclear and mitochondrial DNAs. All these results lead us to the possibility that there is a novel type of DNA in microbodies.

Electron Microscopic Observation of Biological Specimens in Their Native State by Employing Cryogenic Techniques

1972 ◽  
Vol 30 ◽  
pp. 410-411 ◽  
Author(s):  
Tokio Nei ◽  
Haruo Yotsumoto ◽  
Yoichi Hasegawa ◽  
Yuji Nagasawa
Keyword(s):  
Electron Microscopic Observation ◽  
Surface Structures ◽  
Specimen Preparation ◽  
Native State ◽  
Electron Microscopic ◽  
Biological Specimen ◽  
Specimen Holder ◽  
Cold Stage ◽  
Preparation Techniques ◽  
Scanning Electron

In order to observe biological specimens in their native state, that is, still containing their water content, various methods of specimen preparation have been used, the principal two of which are the chamber method and the freeze method.Using its recently developed cold stage for installation in the pre-evacuation chamber of a scanning electron microscope, we have succeeded in directly observing a biological specimen in its frozen state without the need for such conventional specimen preparation techniques as drying and metallic vacuum evaporation. (Echlin, too, has reported on the observation of surface structures using the same freeze method.)In the experiment referred to herein, a small sliced specimen was place in the specimen holder. After it was rapidly frozen by freon cooled with liquid nitrogen, it was inserted into the cold stage of the specimen chamber.

Sign in / Sign up

Export Citation Format

Share Document