-
Zeitschrift Fur Medizinische Physik Feb 2022
Topics: Phantoms, Imaging; Proton Therapy; Protons; Radiography; Tomography; Tomography, X-Ray Computed
PubMed: 34930684
DOI: 10.1016/j.zemedi.2021.11.005 -
Biomolecules Oct 2022One of the most common biochemical processes is the proton transfer through the cell membranes, having significant physiological functions in living organisms. The... (Review)
Review
One of the most common biochemical processes is the proton transfer through the cell membranes, having significant physiological functions in living organisms. The proton translocation mechanism has been extensively studied; however, mechanistic details of this transport are still needed. During the last decades, the field of artificial proton channels has been in continuous growth, and understanding the phenomena of how confined water and channel components mediate proton dynamics is very important. Thus, proton transfer continues to be an active area of experimental and theoretical investigations, and acquiring insights into the proton transfer mechanism is important as this enlightenment will provide direct applications in several fields. In this review, we present an overview of the development of various artificial proton channels, focusing mostly on their design, self-assembly behavior, proton transport activity performed on bilayer membranes, and comparison with protein proton channels. In the end, we discuss their potential applications as well as future development and perspectives.
Topics: Protons; Biomimetics; Ion Channels; Ion Transport; Water
PubMed: 36291682
DOI: 10.3390/biom12101473 -
Biochimica Et Biophysica Acta.... Apr 2023
Topics: Protons; Hydrogen-Ion Concentration; Electron Transport
PubMed: 36775006
DOI: 10.1016/j.bbamem.2023.184139 -
International Journal of Molecular... May 2023Protein molecular machines, also known as proton pumps, are the most important element of biological membranes [...].
Protein molecular machines, also known as proton pumps, are the most important element of biological membranes [...].
Topics: Proton Pumps; Protons; Biochemical Phenomena; Ion Transport; Cell Membrane
PubMed: 37240416
DOI: 10.3390/ijms24109070 -
Annual Review of Physiology Feb 2024A handful of biological proton-selective ion channels exist. Some open at positive or negative membrane potentials, others open at low or high pH, and some are light... (Review)
Review
A handful of biological proton-selective ion channels exist. Some open at positive or negative membrane potentials, others open at low or high pH, and some are light activated. This review focuses on common features that result from the unique properties of protons. Proton conduction through water or proteins differs qualitatively from that of all other ions. Extraordinary proton selectivity is needed to ensure that protons permeate and other ions do not. Proton selectivity arises from a proton pathway comprising a hydrogen-bonded chain that typically includes at least one titratable amino acid side chain. The enormously diverse functions of proton channels in disparate regions of the phylogenetic tree can be summarized by considering the chemical and electrical consequences of proton flux across membranes. This review discusses examples of cells in which proton efflux serves to increase pH, decrease pH, control the membrane potential, generate action potentials, or compensate transmembrane movement of electrical charge.
Topics: Humans; Protons; Ion Channel Gating; Hydrogen-Ion Concentration; Phylogeny; Ion Channels
PubMed: 37931166
DOI: 10.1146/annurev-physiol-042222-023242 -
Chemical Reviews Jan 2022We present an update and revision to our 2010 review on the topic of proton-coupled electron transfer (PCET) reagent thermochemistry. Over the past decade, the data and... (Review)
Review
We present an update and revision to our 2010 review on the topic of proton-coupled electron transfer (PCET) reagent thermochemistry. Over the past decade, the data and thermochemical formalisms presented in that review have been of value to multiple fields. Concurrently, there have been advances in the thermochemical cycles and experimental methods used to measure these values. This Review (i) summarizes those advancements, (ii) corrects systematic errors in our prior review that shifted many of the absolute values in the tabulated data, (iii) provides updated tables of thermochemical values, and (iv) discusses new conclusions and opportunities from the assembled data and associated techniques. We advocate for updated thermochemical cycles that provide greater clarity and reduce experimental barriers to the calculation and measurement of Gibbs free energies for the conversion of X to XH in PCET reactions. In particular, we demonstrate the utility and generality of reporting potentials of hydrogenation, °(V vs H), in almost any solvent and how these values are connected to more widely reported bond dissociation free energies (BDFEs). The tabulated data demonstrate that °(V vs H) and BDFEs are generally insensitive to the nature of the solvent and, in some cases, even to the phase (gas versus solution). This Review also presents introductions to several emerging fields in PCET thermochemistry to give readers windows into the diversity of research being performed. Some of the next frontiers in this rapidly growing field are coordination-induced bond weakening, PCET in novel solvent environments, and reactions at material interfaces.
Topics: Electron Transport; Electrons; Indicators and Reagents; Protons
PubMed: 34928136
DOI: 10.1021/acs.chemrev.1c00521 -
International Journal of Molecular... Jun 2022The advancement of super-resolution imaging (SRI) relies on fluorescent proteins with novel photochromic properties. Using light, the reversibly switchable fluorescent... (Review)
Review
The advancement of super-resolution imaging (SRI) relies on fluorescent proteins with novel photochromic properties. Using light, the reversibly switchable fluorescent proteins (RSFPs) can be converted between bright and dark states for many photocycles and their emergence has inspired the invention of advanced SRI techniques. The general photoswitching mechanism involves the chromophore - isomerization and proton transfer for negative and positive RSFPs and hydration-dehydration for decoupled RSFPs. However, a detailed understanding of these processes on ultrafast timescales (femtosecond to millisecond) is lacking, which fundamentally hinders the further development of RSFPs. In this review, we summarize the current progress of utilizing various ultrafast electronic and vibrational spectroscopies, and time-resolved crystallography in investigating the on/off photoswitching pathways of RSFPs. We show that significant insights have been gained for some well-studied proteins, but the real-time "action" details regarding the bidirectional - isomerization, proton transfer, and intermediate states remain unclear for most systems, and many other relevant proteins have not been studied yet. We expect this review to lay the foundation and inspire more ultrafast studies on existing and future engineered RSFPs. The gained mechanistic insights will accelerate the rational development of RSFPs with enhanced two-way switching rate and efficiency, better photostability, higher brightness, and redder emission colors.
Topics: Crystallography; Green Fluorescent Proteins; Luminescent Proteins; Protons; Spectrum Analysis
PubMed: 35742900
DOI: 10.3390/ijms23126459 -
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 -
The Ulster Medical Journal Jan 2021
Topics: History, 20th Century; Humans; Nobel Prize; Protons
PubMed: 33642630
DOI: No ID Found -
Frontiers in Bioscience (Landmark... Jan 2023The maintenance of intracellular and extracellular pH relies on multiple ion transporters/channels. Proton-activated chloride channel (PAC) precisely regulates... (Review)
Review
The maintenance of intracellular and extracellular pH relies on multiple ion transporters/channels. Proton-activated chloride channel (PAC) precisely regulates extracellular and early/late endosomal pH by transporting chloride ion (Cl-) across membranes and has been shown to be implicated in pH imbalance under hypoxic conditions, such as the acidic microenvironments of cancer and ischemia. In this article, the phenotypic characteristics, molecular mechanisms, physiology of PAC and its role in cancer, ischemic stroke and hypoxia will be discussed in order to provide some clues for developing potential therapeutic strategies.
Topics: Humans; Chloride Channels; Chlorides; Protons; Biological Transport; Hypoxia
PubMed: 36722267
DOI: 10.31083/j.fbl2801011