Search results for "hydrogen"
showing 10 items of 4254 documents
Characterization of sulfhydryl oxidase from Aspergillus tubingensis
2017
Background Despite of the presence of sulfhydryl oxidases (SOXs) in the secretomes of industrially relevant organisms and their many potential applications, only few of these enzymes have been biochemically characterized. In addition, basic functions of most of the SOX enzymes reported so far are not fully understood. In particular, the physiological role of secreted fungal SOXs is unclear. Results The recently identified SOX from Aspergillus tubingensis (AtSOX) was produced, purified and characterized in the present work. AtSOX had a pH optimum of 6.5, and showed a good pH stability retaining more than 80% of the initial activity in a pH range 4-8.5 within 20 h. More than 70% of the initia…
Identification and structural characterization of LytU, a unique peptidoglycan endopeptidase from the lysostaphin family
2017
AbstractWe introduce LytU, a short member of the lysostaphin family of zinc-dependent pentaglycine endopeptidases. It is a potential antimicrobial agent for S. aureus infections and its gene transcription is highly upregulated upon antibiotic treatments along with other genes involved in cell wall synthesis. We found this enzyme to be responsible for the opening of the cell wall peptidoglycan layer during cell divisions in S. aureus. LytU is anchored in the plasma membrane with the active part residing in the periplasmic space. It has a unique Ile/Lys insertion at position 151 that resides in the catalytic site-neighbouring loop and is vital for the enzymatic activity but not affecting the …
Hydrogen Bond Fluctuations Control Photochromism in a Reversibly Photo-Switchable Fluorescent Protein
2015
Reversibly switchable fluorescent proteins (RSFPs) are essential for high-resolution microscopy of biological samples, but the reason why these proteins are photochromic is still poorly understood. To address this problem, we performed molecular dynamics simulations of the fast switching Met159Thr mutant of the RSFP Dronpa. Our simulations revealed a ground state structural heterogeneity in the chromophore pocket that consists of three populations with one, two, or three hydrogen bonds to the phenolate moiety of the chromophore. By means of non-adiabatic quantum mechanics/molecular dynamics simulations, we demonstrated that the subpopulation with a single hydrogen bond is responsible for of…
Extracellular electrical recording of pH-triggered bursts in C6 glioma cell populations
2016
Extracellular electrode recording demonstrates acid-triggered electrical activity in glioma cell populations.
Histidine tracts in human transcription factors: insight into metal ion coordination ability
2017
Consecutive histidine repeats are chosen both by nature and by molecular biologists due to their high affinity towards metal ions. Screening of the human genome showed that transcription factors are extremely rich in His tracts. In this work, we examine two of such His-rich regions from forkhead box and MAFA proteins—MB3 (contains 18 His) and MB6 (with 21 His residues), focusing on the affinity and binding modes of Cu2+ and Zn2+ towards the two His-rich regions. In the case of Zn2+ species, the availability of imidazole nitrogen donors enhances metal complex stability. Interestingly, an opposite tendency is observed for Cu2+ complexes at above physiological pH, in which amide nitrogens part…
Aerobic catabolism and respiratory lactate bypass in Ndh-negative Zymomonas mobilis
2018
Ability to ferment in the presence of oxygen increases the robustness of bioprocesses and opens opportunity for novel industrial setups. The ethanologenic bacterium Zymomonas mobilis performs rapid and efficient anaerobic ethanol fermentation, yet its respiratory NADH dehydrogenase (Ndh)-deficient strain (ndh-) is known to produce ethanol with high yield also under oxic conditions. Compared to the wild type, it has a lower rate of oxygen consumption, and an increased expression of the respiratory lactate dehydrogenase (Ldh). Here we present a quantitative study of the product spectrum and carbon balance for aerobically growing ndh-. Ldh-deficient and Ldh-overexpressing ndh- strains were con…
Unraveling the Molecular Mechanism of Action of Empagliflozin in Heart Failure With Reduced Ejection Fraction With or Without Diabetes
2019
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Anticancer properties of 5Z-(4- fuorobenzylidene)-2-(4- hydroxyphenylamino)-thiazol-4-one
2019
Abstract4-thiazolidinones, which are privileged structures in medicinal chemistry, comprise the well-known class of heterocycles and are a source of new drug-like compounds. Undoubtedly, the 5-bulky-substituted-2,4-thiazolidinediones - a class of antihyperglycemic glitazones, which are peroxisome proliferator-activated receptor gamma (PPARγ) agonists, are the most described group among them. As there are various chemically distinct 4-thiazolidinones, different subtypes have been selected for studies; however, their main pharmacological profiles are similar. The aim of this study was to evaluate the anticancer activity of 5Z-(4-fluorobenzylidene)-2-(4-hydroxyphenylamino)-thiazol-4-one (Les-2…
Enrichment of Bacterioplankton Able to Utilize One-Carbon and Methylated Compounds in the Coastal Pacific Ocean
2018
International audience; Understanding the temporal variations and succession of bacterial communities involved in the turnover of one-carbon and methylated compounds is necessary to better predict bacterial impacts on the marine carbon cycle and air-sea carbon fluxes. The ability of the local bacterioplankton community to exploit one-carbon and methylated compounds as main source of bioavailable carbon during a productive and less productive period was assessed through enrichment experiments. Surface seawater was amended with methanol and trimethylamine-N-oxide (TMAO), and bacterial abundance, production, oxygen consumption, as well as methanol turnover and growth rates of putative methylot…
Takotsubo Syndrome: Impact of endothelial dysfunction and oxidative stress
2021
Takotsubo Syndrome (TTS) is characterized by a transient left ventricular dysfunction recovering spontaneously within days or weeks. Although the pathophysiology of TTS remains obscure, there is growing evidence suggesting TTS to be associated with increased production of reactive oxygen species (ROS), which may be involved in causing transient coronary and peripheral endothelial dysfunction leading to a transient impairment of myocardial contraction due to stunning (apical ballooning). Endothelial dysfunction is mainly caused by decreased vascular and myocardial nitric oxide bioavailability in response to increased ROS production. Accordingly, studies in humans and animal models demonstrat…