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Biochimica Et Biophysica Acta.... Apr 2023
Topics: Protons; Hydrogen-Ion Concentration; Electron Transport
PubMed: 36775006
DOI: 10.1016/j.bbamem.2023.184139 -
The Ulster Medical Journal Jan 2021
Topics: History, 20th Century; Humans; Nobel Prize; Protons
PubMed: 33642630
DOI: No ID Found -
The Journal of Physical Chemistry. B Jul 2021Superacids have been the source of much spectacular chemistry but very little interesting physics despite the fact that the states of cations formed by transfer of the...
Superacids have been the source of much spectacular chemistry but very little interesting physics despite the fact that the states of cations formed by transfer of the superacid proton to molecular bases can approach that of the cations in free space. Indeed, some of the very strongest acids, such as HPF and HAlCl, have no independent existence due to lack of screening of the bare proton self-energy: their acidities can only be assessed by study of the conjugate bases. Here we show that, by allowing the protons of transient HAlCl and HAlBr to relocate on pentafluoropyridine, PFP (a very weak base that is stable to superacids), we can create glass forming protic ionic liquids (PILs) that are themselves superacids but, being free of superacid vapors, are of benign character. At , conductivities exceed "good" ionic liquid values by 9 decades, so must be superprotonic. Anomalous Walden plots confirm superprotonicity.
Topics: Acids; Cations; Electric Conductivity; Ionic Liquids; Protons
PubMed: 34250812
DOI: 10.1021/acs.jpcb.1c05299 -
Nature Structural & Molecular Biology Jul 2023Proton transport is indispensable for cell life. It is believed that molecular mechanisms of proton movement through different types of proton-conducting molecules have...
Proton transport is indispensable for cell life. It is believed that molecular mechanisms of proton movement through different types of proton-conducting molecules have general universal features. However, elucidation of such mechanisms is a challenge. It requires true-atomic-resolution structures of all key proton-conducting states. Here we present a comprehensive function-structure study of a light-driven bacterial inward proton pump, xenorhodopsin, from Bacillus coahuilensis in all major proton-conducting states. The structures reveal that proton translocation is based on proton wires regulated by internal gates. The wires serve as both selectivity filters and translocation pathways for protons. The cumulative results suggest a general concept of proton translocation. We demonstrate the use of serial time-resolved crystallography at a synchrotron source with sub-millisecond resolution for rhodopsin studies, opening the door for principally new applications. The results might also be of interest for optogenetics since xenorhodopsins are the only alternative tools to fire neurons.
Topics: Protons; Proton Pumps; Ion Transport
PubMed: 37386213
DOI: 10.1038/s41594-023-01020-9 -
Blood Jan 2022
Topics: Bacterial Proteins; Cell Proliferation; Protein Transport; Protons
PubMed: 35084476
DOI: 10.1182/blood.2021014237 -
Biophysical Journal Jun 2022Proton-coupled peptide transporters (POTs) are crucial for the uptake of di- and tripeptides as well as drug and prodrug molecules in prokaryotes and eukaryotic cells....
Proton-coupled peptide transporters (POTs) are crucial for the uptake of di- and tripeptides as well as drug and prodrug molecules in prokaryotes and eukaryotic cells. We illustrate from multiscale modeling how transmembrane proton flux couples within a POT protein to drive essential steps of the full functional cycle: 1) protonation of a glutamate on transmembrane helix 7 (TM7) opens the extracellular gate, allowing ligand entry; 2) inward proton flow induces the cytosolic release of ligand by varying the protonation state of a second conserved glutamate on TM10; 3) proton movement between TM7 and TM10 is thermodynamically driven and kinetically permissible via water proton shuttling without the participation of ligand. Our results, for the first time, give direct computational confirmation for the alternating access model of POTs, and point to a quantitative multiscale kinetic picture of the functioning protein mechanism.
Topics: Glutamic Acid; Ligands; Membrane Transport Proteins; Peptides; Protons
PubMed: 35614850
DOI: 10.1016/j.bpj.2022.05.029 -
Nature Chemistry Aug 2009Enantioselective protonation is a common process in biosynthetic sequences. The decarboxylase and esterase enzymes that effect this valuable transformation are able to... (Review)
Review
Enantioselective protonation is a common process in biosynthetic sequences. The decarboxylase and esterase enzymes that effect this valuable transformation are able to control both the steric environment around the proton acceptor (typically an enolate) and the proton donor (typically a thiol). Recently, several chemical methods to achieve enantioselective protonation have been developed by exploiting various means of enantiocontrol in different mechanisms. These laboratory transformations have proven useful for the preparation of a number of valuable organic compounds.
Topics: Enzymes; Hydrogen; Protons; Stereoisomerism; Substrate Specificity
PubMed: 20428461
DOI: 10.1038/nchem.297 -
Journal of Clinical Oncology : Official... Sep 2014Proton beam therapy, the most common form of heavy-particle radiation therapy, is not a new invention, but it has gained considerable public attention because of the... (Review)
Review
Proton beam therapy, the most common form of heavy-particle radiation therapy, is not a new invention, but it has gained considerable public attention because of the high cost of installing and operating the rapidly increasing number of treatment centers. This article reviews the physical properties of proton beam therapy and focuses on the up-to-date clinical evidence comparing proton beam therapy with the more standard and widely available radiation therapy treatment alternatives. In a cost-conscious era of health care, the hypothetical benefits of proton beam therapy will have to be supported by demonstrable clinical gains. Proton beam therapy represents, through its scale and its cost, a battleground for the policy debate around managing expensive technology in modern medicine.
Topics: Dose-Response Relationship, Radiation; Humans; Neoplasms; Proton Therapy; Protons; Radiotherapy Dosage; Randomized Controlled Trials as Topic
PubMed: 25113772
DOI: 10.1200/JCO.2014.55.1945 -
Journal of Radiation Research Jun 2023
Topics: Protons; Japan; Heavy Ion Radiotherapy; Proton Therapy
PubMed: 37210628
DOI: 10.1093/jrr/rrad034 -
Physiological Reviews Jan 2023The protonation state of soluble and membrane-associated macromolecules dictates their charge, conformation, and functional activity. In addition, protons (H or their... (Review)
Review
The protonation state of soluble and membrane-associated macromolecules dictates their charge, conformation, and functional activity. In addition, protons (H or their equivalents) partake in numerous metabolic reactions and serve as a source of electrochemical energy to drive the transmembrane transport of both organic and inorganic substrates. Stringent regulation of the intracellular pH is therefore paramount to homeostasis. Although the regulation of the cytosolic pH has been studied extensively, our understanding of the determinants of the H concentration ([H]) of intracellular organelles has developed more slowly, limited by their small size and inaccessibility. Recently, however, targeting of molecular probes to the organellar lumen together with advances in genomic, proteomic, and electrophysiological techniques have led to the identification and characterization of unique pumps, channels, and transporters responsible for the establishment and maintenance of intraorganellar pH. These developments and their implications for cellular function in health and disease are the subject of this review.
Topics: Humans; Hydrogen-Ion Concentration; Molecular Probes; Organelles; Proteomics; Protons; Vacuolar Proton-Translocating ATPases
PubMed: 35981302
DOI: 10.1152/physrev.00009.2022