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Proton transport

Xuan Zhang, Ping Zhang, Yi-Gang Weng, Zheng-Zhen Tang, Qin-Yu Zhu, Jie Dai
Tetrathiafulvalene (TTF) derivatives as promising hole transport materials in assembling hybrid halide perovskite solar cells have attracted great attention; however, electron transfer or charge-transfer (CT) between TTF and metal halides has been studied with less detail at the molecular level. Using molecular models, we herein report four new TTF-bismuth-halides assembled by methylated or protonated bis(4'-pyridyl)-tetrathiafulvalene cations, (MePy)2 TTF or (HPy)2 TTF, and bismuth-halide anions. Single crystal analysis showed that the cations are stacked to form a TTF column, and the bismuth-halide anions are inlaid between the TTF columns with anion-cation interactions...
August 14, 2018: Inorganic Chemistry
Valentina Pucino, Danilo Cucchi, Claudio Mauro
Inflammation is associated with the accumulation of lactate at sites of tumour growth and inflammation. Lactate initiates tissue responses contributing to disease. We discuss the potential of targeting lactate transporters in the treatment of cancer and inflammatory conditions. Areas covered: Lactate is the product of glycolysis, which is considered to be a waste metabolite and a fuel for oxidative cells. It is also an active signalling molecule with immunomodulatory and angiogenic properties. They are the consequence of lactate binding to membrane receptor(s) or being transported through specific carrier-mediated transporters across the cellular membrane...
August 14, 2018: Expert Opinion on Therapeutic Targets
Chao Liu, Cheng-Wu Zhang, Shun Qiang Lo, Seok Ting Ang, Katherine Chee Meng Chew, Dejie Yu, Bing Han Chai, Bobby Tan, Fai Tsang, Yee Kit Tai, Bryce Wei Quan Tan, Mui Cheng Liang, Hwee Tong Tan, Jia Ying Tang, Mitchell Kim Peng Lai, John Jia En Chua, Maxey Ching Ming Chung, Sanjay Khanna, Kah-Leong Lim, Tuck Wah Soong
Elevated iron deposition has been reported in Parkinson's disease. However, the route of iron uptake leading to high deposition in the substantia nigra is unresolved. Here, we show a mechanism in enhanced Fe2+ uptake via S-nitrosylation of DMT1. While DMT1 could be S-nitrosylated by exogenous nitric oxide donors, in human PD brains, endogenously S-nitrosylated DMT1 was detected in post-mortem substantia nigra. Patch-clamp electrophysiological recordings and iron uptake assays confirmed increased Mn2+ or Fe2+ uptake through S-nitrosylated DMT1...
August 13, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Gwenael Layec, Gregory M Blain, Matthew J Rossman, Song Y Park, Corey R Hart, Joel D Trinity, Jayson R Gifford, Simranjit K Sidhu, Joshua C Weavil, Thomas J Hureau, Markus Amann, Russell S Richardson
PURPOSE: The impact of an acute bout of exercise, especially high-intensity exercise, on the function of mitochondrial respiratory complexes is not well understood, with potential implications for both the healthy population and patients undergoing exercise based rehabilitation. Therefore, this study sought to comprehensively examine respiratory flux through the different complexes of the electron transport chain (ETC) in skeletal muscle mitochondria before and immediately after high-intensity aerobic exercise...
August 10, 2018: Medicine and Science in Sports and Exercise
Christopher Paul New, Qianqian Ma, Carole Dabney-Smith
Thylakoids are complex sub-organellar membrane systems whose role in photosynthesis makes them critical to life. Thylakoids require the coordinated expression of both nuclear- and plastid-encoded proteins to allow rapid response to changing environmental conditions. Transport of cytoplasmically synthesized proteins to thylakoids or the thylakoid lumen is complex; the process involves transport across up to three membrane systems with routing through three aqueous compartments. Protein transport in thylakoids is accomplished by conserved ancestral prokaryotic plasma membrane translocases containing novel adaptations for the sub-organellar location...
August 12, 2018: Photosynthesis Research
Johannes Stefanski, Christian Schmidt, Sandro Jahn
Hydrothermal diamond anvil cell experiments in combination with Raman spectroscopy and first principles molecular dynamics simulations were performed to investigate the structure and dynamics of aqueous NaOH solutions for temperatures up to 700 °C, pressures up to 850 MPa and two different solute concentrations. The significant changes observed in the O-H stretching region of the Raman spectra between ambient and supercritical conditions are explained by both dynamic effects and structural differences. Especially important are a Grotthuss-like proton transport process and the decreasing network connectivity of the water molecules with increasing temperature...
August 13, 2018: Physical Chemistry Chemical Physics: PCCP
Atreyee Kundu, Subharthi Das, Sourav Basu, Yasufumi Kobayashi, Yuriko Kobayashi, Koyama Hiroyuki, Markkandan Ganesan
The Aluminum (Al) and proton (H+ ) ions are major acid soil stress factors deleteriously affecting plant root growth and crop yield. In our preliminary studies, cotton seedlings (Gossypium hirsutum L.) displayed very sensitive phenotypes to Al and H+ rhizotoxicities. Based on previous Arabidopsis results, we aimed to characterize the Al stress responsive Sensitive to Proton rhizotoxicity 1 (GhSTOP1) transcription system in cotton by RNAi mediated down-regulation. With the help of seed embryo apex explants, we developed transgenic cotton plants overexpressing a GhSTOP1-RNAi cassette with NPTII selection...
August 10, 2018: Plant Biology
Tomotsumi Fujisawa, Masahiro Abe, Jun Tamogami, Takashi Kikukawa, Naoki Kamo, Masashi Unno
Proteorhodopsin (PR) is a microbial rhodopsin functioning as a light-driven proton pump in aquatic bacteria. We performed low-temperature Raman measurements of PR to obtain the structure of the primary photoproduct, the K intermediate (PRK ). PRK showed the hydrogen-out-of-plane modes that are much less intense than those of bacteriorhodopsin as the prototypical light-driven proton pump from haloarchaea. The present results reveal the significantly relaxed chromophore structure in PRK , which can be coupled to the slow kinetics of the K intermediate...
August 11, 2018: FEBS Letters
Amanda J Stoffer-Bittner, Candace R Alexander, Douglas W Dingman, George S Mourad, Neil P Schultes
Here, we report that a novel nucleobase cation symporter 2 encoded in the genome of the honeybee bacterial pathogen Paenibacillus larvae reveals high levels of amino acid sequence similarity to the Escherichia coli and Bacillus subtilis uric acid and xanthine transporters. This transporter is named P. larvae uric acid permease-like protein (PlUacP). Even though PlUacP displays overall amino acid sequence similarities, has common secondary structures, and shares functional motifs and functionally important amino acids with E...
August 2018: FEBS Open Bio
Victor Ovchinnikov, Tracy A Stone, Charles M Deber, Martin Karplus
Small multidrug resistance (SMR) pumps represent a minimal paradigm of proton-coupled membrane transport in bacteria, yet no high-resolution structure of an SMR protein is available. Here, atomic-resolution structures of the Escherichia coli efflux-multidrug resistance E ( EmrE ) multidrug transporter in ligand-bound form are refined using microsecond molecular dynamics simulations biased using low-resolution data from X-ray crystallography. The structures are compatible with existing mutagenesis data as well as NMR and biochemical experiments, including pKas of the catalytic glutamate residues and the dissociation constant ([Formula: see text]) of the tetraphenylphosphonium+ cation...
August 6, 2018: Proceedings of the National Academy of Sciences of the United States of America
Sunil Nath
A wealth of molecular mechanistic insights has been provided into the coupling of ion transport to ATP synthesis based on a two-ion theory of biological energy coupling. A kinetic scheme that considers the mode of functioning of a single F1 FO -ATP synthase molecule with H+ -A- cotransport and unidirectional rotation of the c-rotor in the membrane-bound FO -portion of the enzyme has been developed. Mathematical analysis leads to a detailed enzyme kinetic model applicable to a population of molecules which is compared with experimental data on the pH dependence of ATP synthesis...
July 29, 2018: Biophysical Chemistry
G Milluzzo, J Pipek, A G Amico, G A P Cirrone, G Cuttone, G Korn, G Larosa, R Leanza, D Margarone, G Petringa, A Russo, F Schillaci, V Scuderi, F Romano
The main purpose of this paper is to quantitatively study the possibility of delivering dose distributions of clinical relevance with laser-driven proton beams. A Monte Carlo application has been developed with the Geant4 toolkit, simulating the ELIMED (MEDical and multidisciplinary application at ELI-Beamlines) transport and dosimetry beam line which is being currently installed at the ELI-Beamlines in Prague (CZ). The beam line will be used to perform irradiations for multidisciplinary studies, with the purpose of demonstrating the possible use of optically accelerated ion beams for therapeutic purposes...
July 31, 2018: Physica Medica: PM
Martin Schulc, Michal Košťál, Evžen Novák, Tomáš Czakoj
The fast leakage neutron spectra have been measured on spherical nickel benchmark assembly of diameter 50 cm. The 252 Cf neutron source with approximate emission of 5.0·108 n/s was placed into the centre of the sphere. Fast neutron spectrum in the range of 1-10 MeV was measured in the distance of 1 m from the sphere centre by means of proton recoil method using scintillation stilbene crystal. The experimental data were compared to transport calculations based on several evaluated nuclear data libraries using MCNP6...
July 24, 2018: Applied Radiation and Isotopes
Mojtaba Mokari, Mohammad Hassan Alamatsaz, Hossein Moeini, Reza Taleei
In order to study the molecular damage induced in the form of single-strand and double-strand breaks by the ionizing radiation at the DNA level, Geant4-DNA Monte Carlo simulation code for complete transportation of primary protons and other secondary particles in liquid water have been employed in this work. To this aim, a B-DNA model and a thorough classification of DNA damage concerning their complexity were used. Strand breaks were assumed to have been primarily originated by direct physical interactions via energy depositions, assuming a threshold energy of 17...
August 3, 2018: Physics in Medicine and Biology
Xin Wu, Ethan N W Howe, Philip A Gale
Transmembrane anion transport has been the focus of a number of supramolecular chemistry research groups for a number of years. Much of this research is driven by the biological relevance of anion transport and the search to find new treatments for diseases such as cystic fibrosis, which is caused by genetic problems leading to faulty cystic fibrosis transmembrane conductance regulator (CFTR) channels, which in turn lead to reduced chloride and bicarbonate transport through epithelial cell membranes. Considerable effort has been devoted to the development of new transporters, and our group along with others have been searching for combinations of organic scaffolds and anion binding groups that produce highly effective transporters that work at low concentration...
July 31, 2018: Accounts of Chemical Research
Sandra A Reza-López, Edwin O Aguirre-Chacón, Blanca Sánchez-Ramírez, Fabiola Guerrero-Salgado, Dora V Chávez-Corral, Margarita Levario-Carrillo
BACKGROUND: Folate plays a fundamental role for fetal development, participating in cell division, embryogenesis, and fetal growth. The fetus depends on maternal supply of folate across the placenta. The objective of this study was to compare the expression of Folate Receptor-α (FR-α), Reduced Folate Carrier (RFC), and Proton Coupled Folate Transporter (PCFT) in placentas from pregnancies complicated with birth defects (BD) and controls. METHODS: Case-control study, including placentas of BD-complicated pregnancies (n = 25) and a control group (n = 25)...
July 31, 2018: Birth Defects Research
Joseph A Fournier, William B Carpenter, Nicholas H C Lewis, Andrei Tokmakoff
Given the critical role of the aqueous excess proton in redox chemistry, determining its structure and the mechanism of its transport in water are intense areas of experimental and theoretical research. The ultrafast dynamics of the proton's hydration structure has made it extremely challenging to study experimentally. Using ultrafast broadband two-dimensional infrared spectroscopy, we show that the vibrational spectrum of the aqueous proton is fully consistent with a protonated water complex broadly defined as a Zundel-like H5 O2 + motif...
July 30, 2018: Nature Chemistry
Jana Shen
No abstract text is available yet for this article.
July 30, 2018: Proceedings of the National Academy of Sciences of the United States of America
Nathan T Hahn, Trevor Seguin, Ka-Cheong Lau, Chen Liao, Brian J Ingram, Kristin Persson, Kevin R Zavadil
Future energy applications rely on our ability to tune liquid intermolecular interactions and achieve designer electrolytes with highly optimized properties. In this work, we demonstrate rational, combined experimental-computational design of a new carba-closo-dodecaborate based salt with enhanced anodic stability for Mg energy storage applications. We first establish, through a careful examination using a range of solvents, the anodic oxidation of a parent anion; the carba-closo-dodecaborate anion at 4.6 V vs Mg0/2+ (2...
July 30, 2018: Journal of the American Chemical Society
Gilles Daigre, Jérôme Cuny, Pierric Lemoine, Maria Amela-Cortes, Serge Paofai, Nathalie Audebrand, Annie Le Gal La Salle, Eric Quarez, Olivier Joubert, Nikolay G Naumov, Stéphane Cordier
The search for new multifunctional materials displaying proton-conducting properties is of paramount necessity for the development of electrochromic devices and supercapacitors as well as for energy conversion and storage. In the present study, proton conductivity is reported for the first time in three molybdenum cluster-based materials: (H)4 [Mo6 Br6 S2 (OH)6 ]-12H2 O and (H)2 [Mo6 X8 (OH)6 ]-12H2 O (X = Cl, Br). We show that the self-assembling of the luminescent [Mo6 L8 i (OH)6 a ]2-/4- cluster units leads to both luminescence and proton conductivity (σ = 1...
July 30, 2018: Inorganic Chemistry
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