Accurate Vertical Electron Detachment Energies and Multiphoton Resonant Photoelectron Spectra of Biochromophore Anions in Aqueous Solution.

We introduce a new methodology for calculating vertical electron detachment energies (VDEs) of biologically relevant chromophores in their deprotonated anionic forms in aqueous solution. It combines a large-scale mixed DFT/EFP/MD approach with the high-level multireference perturbation theory XMCQDPT2 and the Effective Fragment Potential (EFP) method. The methodology includes a multiscale flexible treatment of inner (∼1000 water molecules) and outer (∼18000 water molecules) water shells around a charged solute, capturing both the effects of specific solvation and the properties of bulk water.

Wavelength dependent mechanism of phenolate photooxidation in aqueous solution.

Phenolate photooxidation is integral to a range of biological processes, yet the mechanism of electron ejection has been disputed. Here, we combine femtosecond transient absorption spectroscopy, liquid-microjet photoelectron spectroscopy and high-level quantum chemistry calculations to investigate the photooxidation dynamics of aqueous phenolate following excitation at a range of wavelengths, from the onset of the S-S absorption band to the peak of the S-S band. We find that for ≥ 266 nm, electron ejection occurs from the S state into the continuum associated with the contact pair in which the PhO˙ radical is in its ground electronic state.

Liquid-microjet photoelectron spectroscopy of the green fluorescent protein chromophore.

Green fluorescent protein (GFP), the most widely used fluorescent protein for in vivo monitoring of biological processes, is known to undergo photooxidation reactions. However, the most fundamental property underpinning photooxidation, the electron detachment energy, has only been measured for the deprotonated GFP chromophore in the gas phase. Here, we use multiphoton ultraviolet photoelectron spectroscopy in a liquid-microjet and high-level quantum chemistry calculations to determine the electron detachment energy of the GFP chromophore in aqueous solution.

Mode-Specific Vibrational Autodetachment Following Excitation of Electronic Resonances by Electrons and Photons.

Electronic resonances commonly decay via internal conversion to vibrationally hot anions and subsequent statistical electron emission. We observed vibrational structure in such an emission from the nitrobenzene anion, in both the 2D electron energy loss and 2D photoelectron spectroscopy of the neutral and anion, respectively. The emission peaks could be correlated with calculated nonadiabatic coupling elements for vibrational modes to the electronic continuum from a nonvalence dipole-bound state.

Comparison of Targeted Mass Spectrometry Techniques with an Immunoassay: A Case Study for HSP90α.

Purpose: The objective of this study is to better understand factors governing the variability and sensitivity in SRM and PRM, compared to immunoassay.

Experimental Design: A 2D-LC-MS/MS-based SRM and PRM assay is developed for quantitative measurements of HSP90α in serum. Forty-three control sera are compared by SRM, PRM, and ELISA following the manufacturer's instructions.

A 6-alkylsalicylate histone acetyltransferase inhibitor inhibits histone acetylation and pro-inflammatory gene expression in murine precision-cut lung slices.

Lysine acetylations are post-translational modifications of cellular proteins, that are crucial in the regulation of many cellular processes. Lysine acetylations on histone proteins are part of the epigenetic code regulating gene expression and are installed by histone acetyltransferases. Observations that inflammatory lung diseases, such as asthma and chronic obstructive pulmonary disease, are characterized by increased histone acetyltransferase activity indicate that development of small molecule inhibitors for these enzymes might be a valuable approach towards new therapies for these diseases.

Site-specific quantification of lysine acetylation in the N-terminal tail of histone H4 using a double-labelling, targeted UHPLC MS/MS approach.

We developed a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the site-specific quantification of lysine acetylation in the N-terminal region of histone H4 by combining chemical derivatization at the protein and peptide levels with digestion using chymotrypsin and trypsin. Unmodified ε-amino groups were first modified with propionic acid anhydride and the derivatized protein digested with trypsin and chymotrypsin. The newly formed peptide N-termini were subjected to a second derivatization step with d6- (heavy) or d0- (light) acetic acid anhydride.

[Results of application of a new method for the treatment of hallux valgus of the first toe].

Background: The aim of the present article was to report our experience with the treatment of patients with hallux valgus and to perform comparative analysis of the results of the newly proposed and standard methods for its surgical correction.

Methods: The data on 70patients (101 feet) with hallux valgus that were operated on between 2011 and 2015 in St. Petersburg Hospital No 2 using the new and standard methods were analysed.

The histone acetyltransferase p300 inhibitor C646 reduces pro-inflammatory gene expression and inhibits histone deacetylases.

Lysine acetylations are reversible posttranslational modifications of histone and non-histone proteins that play important regulatory roles in signal transduction cascades and gene expression. Lysine acetylations are regulated by histone acetyltransferases as writers and histone deacetylases as erasers. Because of their role in signal transduction cascades, these enzymes are important players in inflammation.

A panel of regulated proteins in serum from patients with cervical intraepithelial neoplasia and cervical cancer.

We developed a discovery-validation mass-spectrometry-based pipeline to identify a set of proteins that are regulated in serum of patients with cervical intraepithelial neoplasia (CIN) and squamous cell cervical cancer using iTRAQ, label-free shotgun, and targeted mass-spectrometric quantification. In the discovery stage we used a "pooling" strategy for the comparative analysis of immunodepleted serum and revealed 15 up- and 26 down-regulated proteins in patients with early- (CES) and late-stage (CLS) cervical cancer. The analysis of nondepleted serum samples from patients with CIN, CES, an CLS and healthy controls showed significant changes in abundance of alpha-1-acid glycoprotein 1, alpha-1-antitrypsin, serotransferrin, haptoglobin, alpha-2-HS-glycoprotein, and vitamin D-binding protein.

[Ontogenetic aspects of changing lysozyme activity under acute somatic pain].

Objective: Ouraim was to study influence of acute somatic pain on lysozyme activity of rats of different age: newborn, rats after eye opening, rats at the age of a month, adult and old rats.

Methods: Lysozyme activity was checked before pain irritation and 2, 30, 60, 120, 180min afterwards using Dorofeychuk's method in our modification. Pain effect was modeling by electrical stimulation.

Multidimensional separation of tryptic peptides from human serum proteins using reversed-phase, strong cation exchange, weak anion exchange, and fused-core fluorinated stationary phases.

Proteome profiling of crude serum is a challenging task due to the wide dynamic range of protein concentrations and the presence of high-abundance proteins, which cover >90% of the total protein mass in serum. Peptide fractionation on strong cation exchange, weak anion exchange in the electrostatic repulsion hydrophilic interaction chromatography (ERLIC) mode, RP C18 at pH 2.5 (low pH), fused-core fluorinated at pH 2.

Simultaneous serum desalting and total protein determination by macroporous reversed-phase chromatography.

Macroporous reversed-phase (mRP) chromatography was successfully used to develop an accurate and precise method for total protein in serum. The limits of detection (0.83 μg, LOD) and quantification (2.

Glycopeptide enrichment and separation for protein glycosylation analysis.

Protein glycosylation plays key roles in many biological processes. In addition, alterations in protein glycosylation have been related to different diseases, as well as may affect the properties of recombinant proteins used as human therapeutics. For this reason, protein glycosylation analysis is of main interest in biomedical and biopharmaceutical research.

[Myocardial geometry and function in overweight and obese adolescents].

114 obese (BMI > 97th age-sex percentile) and 27 overweight (BMI 85-97th age-sex percentile) adolescents (10-18 years) were studied using tissue Doppler echocardiography for the assessment of the geometry of the left ventricle and it's systolic and diastolic functions. Subjects were age and sex matched and grouped according to BMI: + 1-2 SD (Group 1); + 2-3 SD (Group 2) and + > 3 SD (Group 3). It was established that the process of cardiac remodeling in adolescents begins with an initial thickening of the interventricular septum (IVS) at the background of normal values of the myocardial mass index (MMI).

Thin-layer chromatographic plates with monolithic layer of silica: production, physical-chemical characteristics, separation capabilities.

The technique for production of thin-layer chromatographic plates with fixed monolithic layer of sorbent was developed on the basis of investigation of factors affecting sorption capacity, sorption kinetics and mechanical stability of monoliths. The optimal reaction mixture for sol-gel synthesis of monoliths consisted of tetraethoxysilane, buffer solution with pH 7.4, N,N-dimethylformamide, ethanol, polyethyleneglycol with molecular weight 1000 and cetylpyridinium chloride in molar ratio 1.

Classification of gasoline by octane number and light gas condensate fractions by origin with using dielectric or gas-chromatographic data and chemometrics tools.

The approach for classification of gasoline by octane number and light gas condensate fractions by origin with using dielectric permeability data has been proposed and compared with classification of same samples on the basis of gas-chromatographic data. The precision of dielectric permeability measurements was investigated by using ANOVA. The relative standard deviation of dielectric permeability was in the range from 0.

Aliphatic carboxylic acids and alcohols as efficiency and elution strength enhancers in micellar liquid chromatography.

Micellar liquid chromatography (MLC) uses surfactant solutions as mobile phases with added organic additives to enhance both the elution strength and the chromatographic efficiency. Two aliphatic carboxylic acids (1-butanoic and 1-pentanoic) were used as MLC additives and compared with the two corresponding alcohols (1-butanol, 1-pentanol) in terms of elution strength, efficiency and selectivity. A set of 11 phenol derivatives was used as probe compounds.

Heteroscedasticity of retention factor and adequate modeling in micellar liquid chromatography.

The two concepts of micelle formation (pseudo-phase and mass-action) could be the basis of retention models in micellar liquid chromatography (MLC). The separation of 4-hydroxybenzoic acid esters and seven polyaromatic hydrocarbons were performed to study the repeatability of retention factor in MLC. The full two factor experimental design was used for studying the dependence of retention factor variance on mobile phase composition (sodium dodecylsulfate, 1-butanol).

Aliphatic carboxylic acids as new modifiers for separation of 2,4-dinitrophenyl amino acids by micellar liquid chromatography.

The possibilities of isocratic separation of 2,4-dinitrophenyl derivatives of 12 amino acids that considerably differ in hydrophobicity by micellar mobile phases with different organic modifiers have been discussed. For the first time aliphatic carboxylic acids have been used as modifiers of micellar eluent in micellar liquid chromatography with C18 columns. Elution strength of hybrid micellar phases on the basis of sodium dodecylsulfate and aliphatic carboxylic acids increases in sequence: acetic View Article and Find Full Text PDF

Micellar liquid chromatography retention model based on mass-action concept of micelle formation.

Mass-action model of surfactant micelle formation has been used to develop a conceptual retention model in micellar liquid chromatography (MLC). The retention model bases on the consideration of the changes of the sorbate microenvironment at its transferring from the mobile phase (hybrid micellar eluent) to the stationary phase (a modified surface of alkyl-bounded sorbent). Principal retention equation contains the characteristics of hybrid micelles (critical micelle concentration, degree of counterion binding, partition coefficient of modifier between aqueous solution and micellar pseudo-phase) as well as three fitting parameters.