Biomaterial Database

Characterization of ion channels involved in the penetration of phage T4 DNA into Escherichia coli cells. 1988

P Boulanger, and L Letellier

Laboratoire des Biomembranes, U.A. 1116, Université Paris Sud, Orsay, France.

The hypothesis of a channel-mediated transport of phage DNA into Escherichia coli cytoplasmic membrane has been formulated for a long time. In this paper, we present experimental evidence in favor of this proposal. We have analyzed the kinetics of the K+ efflux induced by T4 phage and ghosts (phage depleted of DNA) using a potassium selective electrode. We show that the K+ efflux is not catalyzed by the K+ transport systems. The Km of K+ efflux is the same for phage and ghosts. The rate of K+ efflux is linearly related to the multiplicity of infection. This suggests that phage and ghosts induce the formation of similar channels and that one channel is induced by one virion. The K+ efflux is associated with an influx of H+ and Na+ or Li+ which compete for entry through the channel. These ion fluxes may be responsible for the cell depolarization. The phage-induced channels allow the passage of DNA. They are only transiently opened, and their closing leads to cellular repolarization. The ghost-induced channels remain open. The insertion and conformation of the channels in the membrane depend on the temperature and their confirmation is voltage-dependent. We give an estimate of their size.

UI	MeSH Term	Description	Entries
D007473	Ion Channels	Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.	Membrane Channels,Ion Channel,Ionic Channel,Ionic Channels,Membrane Channel,Channel, Ion,Channel, Ionic,Channel, Membrane,Channels, Ion,Channels, Ionic,Channels, Membrane
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008094	Lithium	An element in the alkali metals family. It has the atomic symbol Li, atomic number 3, and atomic weight [6.938; 6.997]. Salts of lithium are used in treating BIPOLAR DISORDER.	Lithium-7,Lithium 7
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011522	Protons	Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.	Hydrogen Ions,Hydrogen Ion,Ion, Hydrogen,Ions, Hydrogen,Proton
D002414	Cations, Monovalent	Positively charged atoms, radicals or group of atoms with a valence of plus 1, which travel to the cathode or negative pole during electrolysis.	Monovalent Cation,Cation, Monovalent,Monovalent Cations
D004279	DNA, Viral	Deoxyribonucleic acid that makes up the genetic material of viruses.	Viral DNA
D004492	Edetic Acid	A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.	EDTA,Edathamil,Edetates,Ethylenediaminetetraacetic Acid,Tetracemate,Calcium Disodium Edetate,Calcium Disodium Versenate,Calcium Tetacine,Chelaton 3,Chromium EDTA,Copper EDTA,Coprin,Dicobalt EDTA,Disodium Calcitetracemate,Disodium EDTA,Disodium Ethylene Dinitrilotetraacetate,Distannous EDTA,Edetate Disodium Calcium,Edetic Acid, Calcium Salt,Edetic Acid, Calcium, Sodium Salt,Edetic Acid, Chromium Salt,Edetic Acid, Dipotassium Salt,Edetic Acid, Disodium Salt,Edetic Acid, Disodium Salt, Dihydrate,Edetic Acid, Disodium, Magnesium Salt,Edetic Acid, Disodium, Monopotassium Salt,Edetic Acid, Magnesium Salt,Edetic Acid, Monopotassium Salt,Edetic Acid, Monosodium Salt,Edetic Acid, Potassium Salt,Edetic Acid, Sodium Salt,Ethylene Dinitrilotetraacetate,Ethylenedinitrilotetraacetic Acid,Gallium EDTA,Magnesium Disodium EDTA,N,N'-1,2-Ethanediylbis(N-(carboxymethyl)glycine),Potassium EDTA,Stannous EDTA,Versenate,Versene,Acid, Edetic,Acid, Ethylenediaminetetraacetic,Acid, Ethylenedinitrilotetraacetic,Calcitetracemate, Disodium,Dinitrilotetraacetate, Disodium Ethylene,Dinitrilotetraacetate, Ethylene,Disodium Versenate, Calcium,EDTA, Chromium,EDTA, Copper,EDTA, Dicobalt,EDTA, Disodium,EDTA, Distannous,EDTA, Gallium,EDTA, Magnesium Disodium,EDTA, Potassium,EDTA, Stannous,Edetate, Calcium Disodium,Ethylene Dinitrilotetraacetate, Disodium,Tetacine, Calcium,Versenate, Calcium Disodium
D004563	Electrochemistry	The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.	Electrochemistries