Structural characterization and thermal stability of Notothenia coriiceps metallothionein

2001 ◽  
Vol 354 (2) ◽  
pp. 291-299 ◽  
Author(s):  
Sabato D'AURIA ◽  
Vincenzo CARGINALE ◽  
Rosaria SCUDIERO ◽  
Orlando CRESCENZI ◽  
Daniela DI MARO ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Antarctic Fish ◽  
Metal Mobility ◽  
Effect Of Temperature ◽  
Amino Acid Residues ◽  
Cd Spectra ◽  
Multinuclear Nmr Spectroscopy ◽  
Notothenia Coriiceps ◽  
Mammalian Metallothioneins ◽  
Thermal Stability Of

Fish and mammalian metallothioneins (MTs) differ in the amino acid residues placed between their conserved cysteines. We have expressed the MT of an Antarctic fish, Notothenia coriiceps, and characterized it by means of multinuclear NMR spectroscopy. Overall, the architecture of the fish MT is very similar to that of mammalian MTs. However, NMR spectroscopy shows that the dynamic behaviour of the two domains is markedly different. With the aid of absorption and CD spectroscopies, we studied the conformational and electronic features of fish and mouse recombinant Cd-MT and the changes produced in these proteins by heating. When the temperature was increased from 20 to 90°C, the Cd-thiolate chromophore absorbance at 254nm of mouse MT was not modified up to 60°C, whereas the absorbance of fish MT decreased significantly starting from 30°C. The CD spectra also changed quite considerably with temperature, with a gradual decrease of the positive band at 260nm that was more pronounced for fish than for mouse MT. The differential effect of temperature on fish and mouse MTs may reflect a different stability of metal-thiolate clusters of the two proteins. Such a conclusion is also corroborated by results showing differences in metal mobility between fish and mouse Zn-MT.

Synthesis of Stabilized Phosphinidenoid Complexes Using Weakly Coordinating Cations

2011 ◽  
Vol 64 (12) ◽  
pp. 1583 ◽  
Author(s):  
Lili Duan ◽  
Vitaly Nesterov ◽  
Jason W. Runyon ◽  
Gregor Schnakenburg ◽  
Anthony J. Arduengo III ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nmr Spectroscopy ◽  
Single Crystal ◽  
X Ray ◽  
Multinuclear Nmr ◽  
Tert Butyl ◽  
Multinuclear Nmr Spectroscopy ◽  
Complex Salts ◽  
Weakly Coordinating ◽  
Thermal Stability Of

The formation of phosphinidenoid complex salts having weakly coordinating cations (WCCs) is reported via treatment of P-functional phosphane complexes with N,N’-di-tert-butyl imidazol-2-ylidene or a P4-t-Bu phosphazene base. The thermal stability of phosphinidenoid complex salts is dependent upon the P–X substituents and the nature of the WCC. The complexes were characterized by multinuclear NMR spectroscopy and confirmed by single-crystal X-ray structure.

Synthesis and conformation of sequential basic polypeptides with branched and linear side chains

1985 ◽  
Vol 50 (12) ◽  
pp. 2925-2936 ◽  
Author(s):  
Štěpánka Štokrová ◽  
Jan Pospíšek ◽  
Jaroslav Šponar ◽  
Karel Bláha
Keyword(s):  
Amino Acid ◽  
Salt Concentration ◽  
Salt Solution ◽  
Theoretical Work ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Cd Spectra ◽  
Low Salt ◽  
Conformational Freedom ◽  
Basic Polypeptides

Polypeptides (Lys-X-Ala)n and (Lys-X-Gly)n in which X represents residues of isoleucine and norleucine, respectively, and polypeptide (Tle-Lys-Ala)n, were synthesized via polymerization of 1-hydroxysuccinimidyl esters of the appropriate tripeptides to complete previously studied series. Circular dichroism (CD) spectra of the respective polymers were measured as a function of pH and salt concentration of the medium. The results were correlated with those obtained previously with the same series containing different amino acid residues at the X-position. The helix forming ability of the polypeptides (Lys-X-Ala)n with linear X side chain was found to be independent of the length. In the series (Lys-X-Gly)n the unordered conformation was the most probable one except (Lys-Ile-Gly)n. This polymer assumed the β conformation even in low salt solution at neutral pH. An agreement with some theoretical work concerned with the restriction of conformational freedom of amino acid residue branching at Cβ atom with our experimental results is evident.

Effect of temperature on chiroptical and conformational properties of acyclic ketoses

1980 ◽  
Vol 45 (2) ◽  
pp. 475-481
Author(s):  
Slavomír Bystrický ◽  
Tibor Sticzay ◽  
Igor Tvaroška
Keyword(s):  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Conformational Mobility ◽  
Effect Of Temperature ◽  
Chemical Calculation ◽  
Cd Spectra ◽  
Conformational Properties ◽  
Temperature Dependences

Conformational mobility of tetruloses, 2-pentuloses, D-3-pentulose and 4-deoxy-L-pentulose was studied by measuring temperature dependences of CD spectra in the region +40°C to -140°C in a methanol-ethanol (1:4) mixture. The changes in spectra reflect the population of rotamers around bonds to the carbonyl chromophore. The most stable conformers were determined by PCILO quantum chemical calculation.

Unusual Rearrangement of Naphthalene in the Synthesis of a Novel B8-B8-Bridged Derivative in the [(1,2-C2B9H11)2-3-Co]- Series. X-Ray Structure and 11B NMR Spectra of [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- (CH3)4N+

1997 ◽  
Vol 62 (5) ◽  
pp. 746-751 ◽  
Author(s):  
Andreas Franken ◽  
Jaromír Plešek ◽  
Christiane Nachtigal
Keyword(s):  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Nucleophilic Substitution ◽  
Nmr Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Unusual Rearrangement ◽  
Multinuclear Nmr Spectroscopy ◽  
11B Nmr ◽  
Isolated Compound

On treatment of the [(1,2-C2B9H11)2Co]- ion with naphthalene in presence of AlCl3 a remarkably bridged [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- ion is obtained as a single isolated compound. The triatomic -CH2-C9H6- bridge is derived from the rearranged naphthalene nucleus. The mechanism of this reaction is obscure but it does resemble the "Electrophile-Induced Nucleophilic Substitution" reported earlier. The structure of the compound was established by multinuclear NMR spectroscopy and by single crystal X-ray diffraction.

scholarly journals Fine structure of the retinal pigment epithelium and cones of Antarctic fish Notohenia coriiceps Richardson in light and dark-conditions

2007 ◽  
Vol 24 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Lucélia Donatti ◽  
Edith Fanta
Keyword(s):  
Epithelial Cells ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Antarctic Fish ◽  
Basal Region ◽  
Dense Cytoplasm ◽  
Transmission Electron ◽  
Notothenia Coriiceps ◽  
The Antarctic ◽  
Pigment Epithelial Cells

The Antarctic fish Notothenia coriiceps Richardson, 1844 lives in an environment of daily and annual photic variation and retina cells have to adjust morphologically to environmental luminosity. After seven day dark or seven day light acclimation of two groups of fish, retinas were extracted and processed for light and transmission electron microscopy. In seven day dark adapted, retina pigment epithelium melanin granules were aggregated at the basal region of cells, and macrophages were seen adjacent to the apical microvilli, between the photoreceptors. In seven day light adapted epithelium, melanin granules were inside the apical microvilli of epithelial cells and macrophages were absent. The supranuclear region of cones adapted to seven day light had less electron dense cytoplasm, and an endoplasmic reticulum with broad tubules. The mitochondria in the internal segment of cones adapted to seven day light were larger, and less electron dense. The differences in the morphology of cones and pigment epithelial cells indicate that N. coriiceps has retinal structural adjustments presumably optimizing vision in different light conditions.

Metal (Fe, Zn, Mn and Cu) levels in the Antarctic fish Notothenia coriiceps

Polar Biology ◽  
1998 ◽  
Vol 20 (6) ◽  
pp. 404-408 ◽  
Author(s):  
M. Márquez ◽  
C. Vodopivez ◽  
R. Casaux ◽  
A. Curtosi
Keyword(s):  
Antarctic Fish ◽  
Notothenia Coriiceps ◽  
The Antarctic
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