In multidomain proteins, individual domains connected by flexible linkers are dynamically rearranged upon ligand binding and sensing changes in environmental factors, such as pH and temperature. Here, we characterize dynamic domain rearrangements of Lys48-linked ubiquitin (Ub) chains as models of multidomain proteins in which molecular surfaces mediating intermolecular interactions are involved in intramolecular domain-domain interactions. Using NMR and other biophysical techniques, we characterized dynamic conformational interconversions of diUb between open and closed states regarding solvent exposure of the hydrophobic surfaces of each Ub unit, which serve as binding sites for various Ub-interacting proteins.
View Article and Find Full Text PDFIn this protocol, we describe the application of a halogen(I) complex as a highly active non-metallic complex catalyst. Specifically, we present a detailed guide to synthesize the halogen(I) complex catalyst and utilize it as an anion-binding catalyst for the Mukaiyama-Mannich-type reaction of N-heteroaromatics such as pyridines. By utilizing a simple catalyst preparation approach and relatively low catalyst loading, the steps outlined in this protocol contribute to the rapid development of useful substances such as pharmaceuticals and functional materials.
View Article and Find Full Text PDFThe three-center-four-electron halogen bond (3c4e X-bond) presents a fundamental design concept for catalysis. By integrating halogen(I) (X: I or Br), the bis-pyridyl ligand , and a non-nucleophilic counteranion Y, we developed non-metallic complex catalysts, [···X···]Ys, that exhibited outstanding activity and facilitated the Mukaiyama-Mannich-type reaction of -heteroaromatics with parts-per-million-level catalyst loading. The high activity of [···X···]SbF was clearly demonstrated.
View Article and Find Full Text PDFA catalytic asymmetric methylene migration reaction of ene-aldimines directed by chiral counteranions is developed, with the optimal catalyst identified as phenanthryl-substituted ()-BINOL phosphate. Control experiments and density functional theory computations reveal the importance of the 2-hydroxy group of the ene-aldimine and attractive (e.g.
View Article and Find Full Text PDFWe investigated the spatial distribution, mass profiles, and benthic risk assessment of a wide range of methylsiloxanes (MSs), including 7 cyclic MSs (CMSs; D3-D9; the number refers to the number of SiO bonds), 13 linear MSs (LMSs; L3-L15), and 15 modified and other MSs (MMSs) in sediments from the Tokyo Bay catchment basin, Japan. We observed widespread distribution of MSs (ΣCMS, ΣLMS, and ΣMMS) in the sediment samples, with concentrations of 1.0-6180 ng/g dry weight (dw), 1.
View Article and Find Full Text PDFModerately oxidizing thioxanthylium photoredox catalysts that operate under irradiation with green light have been developed. These catalysts exhibit relatively moderate excited-state reduction potentials [(C*/C) = 1.75-1.
View Article and Find Full Text PDFImpurities in nine dietary supplements containing L-tryptophan were evaluated using an HPLC methodology. In five tested products, the total impurities were higher than the thresholds described in the Food Chemical Codex or implemented in the EU for pharmaceutical grade L-tryptophan. In addition, liquid chromatography-mass spectrometry was used to specifically test for the presence of 1,1'-ethylidenebis-L-tryptophan (EBT).
View Article and Find Full Text PDFSingle-crystalline organic semiconductors exhibiting band transport have opened new possibilities for the utilization of efficient charge carrier conduction in organic electronic devices. The epitaxial growth of molecular materials is a promising route for the realization of well-crystallized organic semiconductor p-n junctions for optoelectronic applications enhanced by the improved charge carrier mobility. In this study, the formation of a high-quality crystalline interface upon "quasi-homoepitaxial" growth of bis(trifluoromethyl)dimethylrubrene (fmRub) on the single-crystal surface of rubrene was revealed by using out-of-plane and grazing-incidence X-ray diffraction techniques.
View Article and Find Full Text PDFWe developed a self-propelled capsule endoscope that can be controlled from outside the body with real-time observation. To improve the device, we conducted a clinical trial of total gastrointestinal capsule endoscopy in healthy subjects to ascertain whether our first-generation, self-propelled capsule endoscope was safe and effective for observing the entire human gastrointestinal tract. After adequate gastrointestinal pretreatment, five healthy subjects were instructed to swallow a self-propelling capsule endoscope and the safety of a complete gastrointestinal capsule endoscopy with this device was assessed.
View Article and Find Full Text PDFA quantitative approach for the development of halogen-bonding-driven anion-binding catalysts was studied using 4-substituted perfluorinated iodobenzene. F NMR titrations were used to determine the binding constants K for chloride, and their catalytic activities were evaluated in the allylation reaction of a N-activated pyridine. We discovered that the log K and product yields were linearly correlated, and that they were dependent on the Hammett substituent parameter, σ (r =0.
View Article and Find Full Text PDFThe large production volume of methylsiloxanes (MSs), combined with their high mobility/volatility and persistence, is a matter of concern from the atmospheric pollution perspective. Therefore, we evaluated of the concentrations and emission sources of MSs, including 7 cyclic methylsiloxanes (D3-D9; CMSs, the number refers to the number of Si-O bonds) and 13 linear methylsiloxanes (L3-L15; LMSs) in ambient air collected from Saitama, Japan. This is a first study regarding the evaluation of 20 methylsiloxanes in the Japanese atmosphere.
View Article and Find Full Text PDFA Naphthalene diimide (NDI)-incorporated helical thienoacene was developed. The compound has high electron mobility (1.4 cm2 V-1 s-1) thanks to its two-dimensional π-π interaction assisted by the intermolecular C-HO hydrogen bonding of the NDI moieties.
View Article and Find Full Text PDFA redox potential controlled intermolecular [2 + 2] cross-cycloaddition has been developed in the presence of a thioxanthylium photoredox catalyst. Electron-rich styrenes such as β-bromostyrene ( = +1.61 V vs SCE) were selectively oxidized by a thioxanthylium photoredox catalyst ( (C*/C) = +1.
View Article and Find Full Text PDFPurpose: Body mass index (BMI) is a simple index of weight-to-height that is commonly used to classify people as underweight, overweight or obesity, and high BMI has been clearly linked to increased risk of illness in adults. However, few studies have examined the significance of upper normal weight as a risk factor for the development of chronic kidney disease (CKD) in the general Japanese population.
Methods: We conducted a prospective cohort study designed as part of the Nomura study.
Background: Metabolic syndrome (MetS) is related to the increased risk of major cardiovascular diseases (CVD). The link between high serum total bilirubin (TBL) is cross-sectionally related to MetS and its components. However, whether serum TBL predicts incidence of MetS and its components remains inconclusive.
View Article and Find Full Text PDFBackground: Serum uric acid (SUA) has been shown to be a predictor of renal disease progression in most but not all studies. This study aims to test whether renal function-normalized SUA {i.e, SUA/creatinine (Cr) ratio} is a predictor of decreased renal function among diabetic patients.
View Article and Find Full Text PDFBackground: Metabolic syndrome (MetS) is related to the increased risk of major cardiovascular disease. The link between high serum uric acid (SUA) and creatinine (Cr) levels is causally related to MetS and its components. However, whether renal function-normalized SUA [i.
View Article and Find Full Text PDFPurpose: Neutrophil-to-lymphocyte ratio (NLR) was widely studied as a prognostic marker in various medical and surgical specialties, but its significance in diabetic kidney disease is not yet established.
Methods: The subjects comprised 199 men aged 73 ± 11 (mean ± standard deviation) years and 187 women aged 77 ± 10 years from a rural hospital. We examined the relationship between NLR calculated by analyzing differential leukocyte count in complete blood picture and renal function evaluated by estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease Study Group equation and urinary albumin excretion (UAE).
Ruthenium-catalyzed dimerization of 9-anthrylarylsilanes afforded air-stable V-shaped bisanthracenes bridged by a 7,8-disilabicyclo[3.3.0]octadiene moiety.
View Article and Find Full Text PDFBulk (wet and dry) deposition samples were collected in Saitama Prefecture, Japan throughout a year (February 8, 2012 to February 7, 2013) to estimate the influence of dioxins emitting from waste incinerators on river water quality. The annual deposition flux of dioxins was 3.3ng-toxic equivalent (TEQ)/m/year.
View Article and Find Full Text PDFIntroduction: Metabolic syndrome (MetS) is associated with an increased risk of major cardiovascular events. In women, increased serum uric acid (SUA) levels are associated with MetS and its components. However, whether baseline and changes in SUA predict incidence of MetS and its components remains unclear.
View Article and Find Full Text PDFWe determined the concentrations of halogenated polycyclic aromatic hydrocarbons (XPAHs), some of which are carcinogenic and/or mutagenic compounds, in fly and bottom ashes and stack gas collected from waste incinerators in Japan. The dominant XPAHs in stack gas were consistent with those in the urban atmosphere. The dioxin-like toxic equivalent (TEQ) concentration ranges of the XPAHs in stack gas, fly ash, and bottom ash were 0.
View Article and Find Full Text PDFJ Endocrinol Invest
April 2018
Introduction: Higher glycated hemoglobin (Hb) (HbA1c) is significantly associated with an increased risk of cardiovascular disease (CVD). Serum uric acid (SUA) levels are associated with glucose intolerance and type 2 diabetes. Whether gender-specific differences regarding the relationship between SUA levels and HbA1c exist is unknown.
View Article and Find Full Text PDFPurpose: Chronic kidney disease is a major public health concern. Serum uric acid (SUA) at high levels was oxidative stress agents, and total bilirubin (T-BiL) at mildly increased levels was potent antioxidants, but whether SUA and T-BiL produce an additive interaction for the risk of renal dysfunction remains unclear.
Methods: The subjects comprised 567 men aged 71 ± 8 (mean ± standard deviation) years and 853 women aged 70 ± 8 years from a rural village.