Evaluation of different culture conditions for high-level soluble expression of human cyclin A(2) with pET vector in BL21 (DE3) and spectroscopic characterization of its inclusion body structure

In this paper, we evaluated various parameters of culture condition affecting high-level soluble expression of human cyclin A, in Escherichia coli BL21(DE3), and demonstrated that the highest protein yield was obtained using TB(no glycerol) + 0.5% glucose medium at 25 degrees C. By single immobilized metal ion affinity chromatography, we got highly purified human cyclin A(2) with a yield ranged from 20 to 30 mg/L. By amyloid-diagnostic dye ThT binding and Fourier transform infrared spectroscopy, we observed a significant decrease in alpha-helix content and an increase in beta-sheet structure in cyclin A(2) inclusion body in comparison to its native protein, and confirmed the resemblance of the internal organization of cyclin A(2) inclusion body and amyloid fibrils.

UV-vis spectrophotometric titrations and vibrational spectroscopic characterization of meso-(p-hydroxyphenyl)porphyrins

Sequentially spectrophotometric titrations by sodium hydroxide of meso-tetraphenylporphyrin derivatives bearing one, two, three, or four p-hydroxyl groups result in new types of spectra. The strong new bands appear in the visible region with splitting or broadening of the Soret band and its significant loss of oscillator strength. To understand the molecular origin of these phenomena, the Resonance Raman (RR) and Fourier Transform Infrared (FTIR) experiments are carried out. The results demonstrate that the charges of the deprotonated para-hydroxy substituted meso-tetraphenylporphyrins are localized on the substituents, not delocalized into the pi system of the porphyrin macrocycles and that the ground states of the macrocycles remain essentially unperturbed. Both the related behavior of diprotonated tetrakis(p-(dimethylamino)phenyl) porphyrin and protonated Schiff base porphyrins show that the new bands considered as hyperporphyrin spectra are due to pi(phenoxide anion) --> pi*(porphyrin) transitions, where pi is an orbital on the phenoxide anion substitutent and pi* is a LUMO on the porphyrin.

AN INFRARED SPECTROSCOPIC CHARACTERIZATION OF THE SOLID SOLID BEHAVIOR OF DODECYLAMMONIUM CHLORIDE

The infrared spectra of the bilayer system dodecylammonium chloride has been studied as a function of temperature. Unusual splitting of some vibrational modes helps us to characterize the structure of different solid states. This study provided the evidence for the occurrence of an order-disorder phase transition whose onset occurs at 327 K and its completion ends at 339 K. In the low temperature phase below 327 K, the virgin crystals form a well-ordered phase with all-transhydrocarbon chains. In the intermediate state between 327 and 339 K, the data demonstrate the introduction of intramolecular as well as intermolecular disorder. The coexistence of solid and liquid-crystal-like states is shown by the persistence of factor group splittings together with the existence of defect bands in the wide intermediate temperature range. In the high temperature phase over 339 K the crystals convert to a liquid-crystal-like system with extensive motional and conformational disorder, but still show characteristics in their infrared spectra which indicate the presence of ordered segments in the hexagonal solid phase.

Spectroscopic characterization of prepulsed x-ray laser plasmas

Through the use of time-integrated space-resolved keV spectroscopy, we investigate line plasmas showing gain in Ne-like nickel, copper, and zinc for irradiation using the prepulse technique. The experiments were conducted at 1.06 mu m with the prepulse to main pulse intensity contrast ranging from 10(-6) to 10(-2). The effect of the prepulses on the plasma conditions is inferred through spectroscopic line ratio diagnostics for the electron temperature, the Ne-like ground-state density, and the lateral size of the Ne-like region. It is observed that neither the value of the electronic temperature nor its spatially resolved profile along the linear focus axis varies significantly with the prepulse level, contrary to the lateral width and the density of the Ne-like region in the plasma, which are seen to increase. These results explain, at least in part, why prepulsed x-ray lasers show such high gain and brightness.

XUV spectroscopic characterization of warm dense aluminum plasmas generated by the free-electron-laser FLASH

We report on experiments aimed at the generation and characterization of solid density plasmas at the free-electron laser FLASH in Hamburg. Aluminum samples were irradiated with XUV pulses at 13.5 nm wavelength (92 eV photon energy). The pulses with duration of a few tens of femtoseconds and pulse energy up to 100 mu J are focused to intensities ranging between 10(13) and 10(17) W/cm(2). We investigate the absorption and temporal evolution of the sample under irradiation by use of XUV and optical spectroscopy. We discuss the origin of saturable absorption, radiative decay, bremsstrahlung and atomic and ionic line emission. Our experimental results are in good agreement with simulations.

Spectroscopic characterization of a novel 2 /[4Fe /4S] ferredoxin isolated from Desulfovibrio desulfuricans ATCC 27774

Inorganica Chimica Acta 356 (2003) 215-221

Mass spectroscopic characterization of the coronavirus infectious bronchitis virus nucleoprotein and elucidation of the role of phosphorylation in RNA binding by using surface plasmon resonance

Phosphorylation of the coronavirus nucleoprotein (N protein) has been predicted to play a role in RNA binding. To investigate this hypothesis, we examined the kinetics of RNA binding between nonphosphorylated and phosphorylated infectious bronchitis virus N protein with nonviral and viral RNA by surface plasmon resonance (Biacore). Mass spectroscopic analysis of N protein identified phosphorylation sites that were proximal to RNA binding domains. Kinetic analysis, by surface plasmon resonance, indicated that nonphospborylated N protein bound with the same affinity to viral RNA as phosphorylated N protein. However, phosphorylated N protein bound to viral RNA with a higher binding affinity than nonviral RNA, suggesting that phosphorylation of N protein determined the recognition of virus RNA. The data also indicated that a known N protein binding site (involved in transcriptional regulation) consisting of a conserved core sequence present near the 5' end of the genome (in the leader sequence) functioned by promoting high association rates of N protein binding. Further analysis of the leader sequence indicated that the core element was not the only binding site for N protein and that other regions functioned to promote high-affinity binding.

A novel cation induced polymeric chain in Na-8[{Cu(gly)(2)}(2)]{H-2(H2W12O42)}] center dot 24H(2)O: hydrothermal synthesis, spectroscopic characterization and X-ray structure analysis

A novel bis(glycinato) copper(II) paradodecatungstate Na-8[{Cu(gly)(2)}(2)]-{H-2(H2W12O42)}] center dot 24H(2)O (1) has been synthesized under hydrothermal conditions. The crystal structure of 1 reveals an infinite one-dimensional chain along the [100] direction and is built from paradodecatungstate (H2W12O42)(10-) clusters joined through [Cu(gly)(2)] moieties. Parallel chains are interlinked by NaO6 octahedra to generate a two-dimensional network.