Phosphoproteome Profiling Using a Fluorescent Phosphosensor Dye in Two-Dimensional Polyacrylamide Gel Electrophoresis

We validated the novel PhosphoQUANTI SolidBlue Complex (PQSC) dye for the sensitive fluorescent detection of phosphorylated proteins in polyacrylamide- and two-dimensional gel electrophoresis (PAGE and 2DE, respectively). PQSC can detect as little as 15.6 ng of ß-casein, a pentaphosphorylated protein, and 61.3 ng of ovalbumin, a diphosphorylated protein. Fluorescence intensity correlates with the number of phosphorylated residues on the protein. To demonstrate the specificity of PQSC for phosphoproteins, enzymatically dephosphorylated lysates of Swiss 3T3 cells were separated in 2DE gels and stained by PQSC. The fluorescence signals in these gels were markedly reduced following dephosphorylation. When the phosphorylated proteins in Swiss 3T3 cell lysates were concentrated using a phosphoprotein enrichment column, the majority of phosphoproteins showed fluorescence signals in the pI 4–5 range. Finally, we performed phosphoproteome analysis to study differences in the protein phosphorylation profiles of proliferating and quiescent Swiss 3T3 cells. Over 135 discernible protein spots were detected, from which a selection of 15 spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF-MS). The PQSC staining procedure for phosphoprotein detection is simple, reversible, and fully compatible with MALDI TOF-MS.     

Temperature dependent dendritic domain shapes in Langmuir monolayers of tetradecanoyl N-ethanolamide at the air-water interface

The effect of temperature on the surface phase behavior of tetradecanoyl N-ethanolamide (NHEA-14) in Langmuir monolayers at the air-water interface has been investigated by film balance and Brewster angle microscopy (BAM). It has been observed that dendritic domains are formed in the coexistence region between liquid-expanded (LE) and liquid-condensed (LC) phases at different temperatures. At 10 and 15°C, the domains are four-armed dendrites having wide arms which have a tendency to be fractal while growing in size. At 20°C, five-armed dendritic domains are formed. At a temperature higher than 20°C, the domains are mainly six-armed dendrites having very narrow and sharp arms. The formation of dendritic domains should be due to the presence of interfacial hydrogen bonding among the head groups of the amphiphile. Increased dehydration of the head groups with an increase in the temperature should be responsible for the temperature dependency of the dendritic domain shapes in the monolayers of NHEA-14.     

Peptide bond formation by aminolysin-A catalysis: a simple approach to enzymatic synthesis of diverse short oligopeptides and biologically active puromycins

A new S9 family aminopeptidase derived from the actinobacterial thermophile Acidothermus cellulolyticus was cloned and engineered into a transaminopeptidase by site-directed mutagenesis of catalytic Ser(491) into Cys. The engineered biocatalyst, designated aminolysin-A, can catalyze the formation of peptide bonds to give linear homo-oligopeptides, hetero-dipeptides, and cyclic dipeptides using cost-effective substrates in a one-pot reaction. Aminolysin-A can recognize several C-terminal-modified amino acids, including the l- and d-forms, as acyl donors as well as free amines, including amino acids and puromycin aminonucleoside, as acyl acceptors. The absence of amino acid esters prevents the formation of peptides; therefore, the reaction mechanism involves aminolysis and not a reverse reaction of hydrolysis. The aminolysin system will be a beneficial tool for the preparation of structurally diverse peptide mimetics by a simple approach.     

A hydrogenase model system based on the sequence of cytochrome c: photochemical hydrogen evolution in aqueous media

The diiron carbonyl cluster is held by a native CXXC motif, which includes Cys14 and Cys17, in the cytochrome c sequence. It is found that the diiron carbonyl complex works well as a catalyst for H(2) evolution. It has a TON of ～80 over 2 h at pH 4.7 in the presence of a Ru-photosensitizer and ascorbate as a sacrificial reagent in aqueous media.     

Templated assembly of organic-inorganic materials using the core shell structure of the P22 bacteriophage

Biomimetic chemistry offers new approaches to supramolecular materials synthesis and assembly. We have demonstrated that an assembled viral protein cage, comprising an organic core-shell structure, can be used as a template for the size constrained synthesis of Fe(2)O(3). Particle nucleation is directed by the inner scaffold protein layer, while the size constraints are determined by the outer capsid layer.     

Stereoselective synthesis of amphiasterin B4: assignment of absolute configuration

The first asymmetric synthesis of (+)-amphiasterin B4 was completed from a known (S)-β-benzyloxy-γ-lactone. Comparison with the spectroscopic properties reported for authentic material has given a clear indication as to the absolute stereochemistry of the natural amphiasterin B4.     

Stereoselective synthesis of tetrasubstituted (Z)-alkenes from aryl alkyl ketones utilizing the Horner-Wadsworth-Emmons reaction

Tetrasubstituted (Z)-alkenes were readily prepared through the Horner-Wadsworth-Emmons reactions of methyl 2-[bis(2,2,2-trifluoroethyl)phosphono]propionate with aryl alkyl ketones by employing Sn(OSO(2)CF(3))(2) and N-ethylpiperidine.     

Diastereoselective imino-aldol condensation of chiral 3-(p-Tolylsulfinyl)-2-furaldimine and ester enolates

(Ss)-3-(p-Tolylsufinyl)-2-furaldimine was synthesized, and condensation of the chiral furaldimine with lithium ester enolates has been examined. The product distribution of the reaction is dependent upon reaction conditions and on the kind of the substituent placed on the esters. Disubstituted ester enolate resulted in the exclusive formation of (4R)-beta-lactam, while unsubstituted, tert-butyl ester enolate preferentially gave (3R)-beta-amino ester. With the monosubstituted ester enolates, the condensation afforded (4R)-beta-lactams and/or (3R)-beta-amino esters as major products. This method has been applied to an efficient route to chiral furyl beta-lactams.     

CFD-PBM approach for the gas-liquid flow in a nanobubble generator with honeycomb structure

In recent years, nanobubble technologies have drawn great attention due to their wide applications in many fields of science and technology. From previous studies, a kind of honeycomb structure for high efficiency nanobubble generation has been proposed. In this paper, the numerical simulations of bubbly flow in the honeycomb structure were performed by using a computational fluid dynamics–population balance model (CFD-PBM) coupled model. The numerical model was based on the Eulerian multiphase model and the population balance model (PBM) was used to calculate the bubble size distribution. The bubble size distributions in the honeycomb structure under different work conditions were predicted. Two different drag force models (Schiller-Naumann model and Tomiyama model) and two different aggregation models (Luo model and turbulent aggregation model) were investigated. Both two drag models gave similar prediction of bubble number density distribution at the outlet. The results obtained from Luo model had better reflection of the trend of number density distribution. The turbulence dissipation rate ε can be used to evaluate the nanobubble generating ability. The water tank was not included in the CFD model in this work. The bubbles in the water tank should be studied in the future.     

Glass-forming Photoconductive Organic Compounds II1: Glass-forming Properties of 1,3,5-Triaryl-2-pyrazolines

Glass-forming properties of 2-pyrazoline derivatives were examined and discussed in terms of the molecular structure. The results show that the molecular shape of 1,3,5-triaryl-2-pyrazolines is responsible for the glass-forming properties of these compounds. Glass transition points of several 1,3,5-triaryl-2-pyrazoline derivatives were measured.