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Encyclopedia > Ion channel

Ion channels are pore-forming proteins that help to establish and control the small voltage gradient that exists across the plasma membrane of all living cells (see cell potential) by allowing the flow of ions down their electrochemical gradient. They are present in the membranes that surround all biological cells. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Horizontal line (use sparingly)d grade for the grade or gradient of roads and other geographic features. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hook from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ... In biological cells that are electrically at rest, the cytosol possesses a uniform electric potential or voltage compared to the extracellular solution. ... An ion is an atom or group of atoms that normally are electrically neutral and achieve their status as an ion by loss or addition of one or more electrons. ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ... Illustration of a lipid bilayer The cell membrane, also called the plasma membrane or plasmalemma and cell surface membrane, is a selectively permeable lipid bilayer which comprises the outer layer of a cell. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hook from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ...

Contents

Basic features

An ion channel is an integral membrane protein or more typically an assembly of several proteins. Such "multi-subunit" assemblies usually involve a circular arrangement of identical or homologous proteins closely packed around a water-filled pore through the plane of the membrane or lipid bilayer.[1] The pore-forming subunit(s) are called the α subunit, while the auxiliary subunits are denoted β, γ, and so on. While some channels permit the passage of ions based solely on charge, the archetypal channel pore is just one or two atoms wide at its narrowest point. It conducts a specific species of ion, such as sodium or potassium, and conveys them through the membrane single file--nearly as quickly as the ions move through free fluid. In some ion channels, passage through the pore is governed by a "gate," which may be opened or closed by chemical or electrical signals, temperature, or mechanical force, depending on the variety of channel. An Integral Membrane Protein (IMP) is a protein molecule (or assembly of proteins) that is permanently attached to the biological membrane. ... In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles (or coassembles) with other protein molecules to form a multimeric or oligomeric protein. ... In biology, two or more structures are said to be homologous if they are alike because of shared ancestry. ... A diagonal molecular slab from the DPPC lipid bilayer simulation1; color scheme: PO4 - green, N(CH3)3 - violet, water - blue, terminal CH3 - yellow, O - red, glycol C - brown, chain C - grey. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39. ...


Biological role

Because "voltage-gated" channels underlie the nerve impulse and because "transmitter-gated" channels mediate conduction across the synapses, channels are especially prominent components of the nervous system. Indeed, most of the offensive and defensive toxins that organisms have evolved for shutting down the nervous systems of predators and prey (e.g., the venoms produced by spiders, scorpions, snakes, fish, bees, sea snails and others) work by plugging ion channel pores. In addition, ion channels figure in a wide variety of biological processes that involve rapid changes in cells, such as cardiac, skeletal, and smooth muscle contraction, epithelial transport of nutrients and ions, T-cell activation and pancreatic beta-cell insulin release. In the search for new drugs, ion channels are a favorite target. Schematic of an electrophysiological recording of an action potential showing the various phases which occur as the wave passes a point on a cell membrane. ... Illustration of the major elements in a prototypical synapse. ... The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and also stops input from the senses, and initiates actions. ... Cardiac muscle is a type of involuntary mononucleated, or uninucleated, striated muscle found exclusively within the heart. ... A top-down view of skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ... Smooth muscle of the aorta. ... A top-down view of skeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle cell (called a muscle fiber) lengthens or shortens. ... Types of epithelium This article discusses the epithelium, an animal anatomical structure. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... HEY YO STUPID GUY ... Insulin (from Latin insula, island, as it is produced in the Islets of Langerhans in the pancreas) is a polypeptide hormone that regulates carbohydrate metabolism. ...


Diversity

  • Voltage-gated sodium channels: Like other voltage-gated channels, these channels open and close in response to membrane potential. This family contains at least 9 members and is largely responsible for action potential creation and propagation. The pore-forming α subunits are very large (up to 4,000 amino acids) and consist of four homologous repeat domains (I-IV) each comprising six transmembrane segments (S1-S6) for a total of 24 transmembrane segments. The members of this family also coassemble with auxiliary β subunits, each spanning the membrane once. Both α and β subunits are extensively glycosylated.
  • Voltage-gated calcium channels: As with the other voltage-gated channels, these open and close according to the membrane potential. This family contains 10 members, though these members are known to coassemble with α2δ, β, and γ subunits. These channels play an important role in both linking muscle excitation with contraction as well as neuronal excitation with transmitter release. The α subunits have an overall structural resemblance to those of the sodium channels and are equally large.
  • Potassium channels: This superfamily is comprised of four families of channels, which are grouped based on homology and activation. Potassium channels are near ubiquitous in their expression and are primarily permeable to potassium over other ions.
  • Voltage-gated potassium channels: Like other voltage-gated channels, these KV channels open and close according to membrane potential. This family contains almost 40 members, which are further divided into 12 subfamilies. These channels are known mainly for their role in repolarizing the cell membrane following action potentials. The α subunits have six transmembrane segments, homologous to a single domain of the sodium channels. Correspondingly, they assemble as tetramers to produce a functioning channel.
  • Calcium-activated potassium channels: This family of channels is, for the most part, activated by intracellular Ca2+ and contains 8 members.
  • Inward-rectifier potassium channels: These channels allow potassium to flow into the cell in an inwardly rectifying manner, i.e, potassium flows effectively into, but not out of, the cell. This family is composed of 15 official and 1 unofficial members and is further subdivided into 7 subfamilies based on homology. These channels are affected by intracellular ATP, PIP2, and G-protein βγ subunits. They are involved in important physiological processes such as the pacemaker activity in the heart, insulin release, and potassium uptake in glial cells. They contain only two transmembrane segments, corresponding to the core pore-forming segments of the KV and KCa channels. Their α subunits form tetramers.
  • Chloride channels: This superfamily of poorly understood channels consists of approximately 13 members.
  • Transient receptor potential channels: This group of channels, normally referred to simply as TRP channels, is named after their role in Drosophila phototransduction. This family, containing at least 28 members, is incredibly diverse in its method of activation. Some TRP channels seem to be constitutively open, while others are gated by voltage, intracellular Ca2+, pH, redox state, osmolarity, and mechanical stretch. These channels also vary according to the ion(s) they pass, some being selective for Ca2+ while others are less selective, acting as cation channels. This family is subdivided into 6 subfamilies based on homology: classical (TRPC), vanilloid receptors (TRPV), melastatin (TRPM), polycystins (TRPP), mucolipins (TRPML), and ankyrin transmembrane protein 1 (TRPA).
  • Cyclic nucleotide-gated channels: This superfamily of channels contains two families: the cyclic nucleotide-gated (CNG) channels and the hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels. It should be noted that this grouping is functional rather than evolutionary.
  • Cyclic nucleotide-gated channels: This family of channels is characterized by activation due to the binding of intracellular cAMP or cGMP, with specificity varying by member. These channels are primarily permeable to monovalent cations such as K+ and Na+. They are also permeable to Ca2+, though it acts to close them. There are 6 members of this family, which is divided into 2 subfamilies.
  • Hyperpolarization-activated, cyclic nucleotide-gated channels: While these channels are voltage-gated, their opening is due to hyperpolarization rather than the depolarization required for other like channels. These channels are also sensitive to the cyclic nucleotides cAMP and cGMP, which alter the voltage sensitivity of the channel’s opening. These channels are permeable to the monovalent cations K+ and Na+. There are 4 members of this family, all of which form tetramers of six-transmembrane α subunits. As these channels open under hyperpolarizing conditions, they function as pacemaking channels in the heart, particularly the SA node.
  • Two-pore channels: This small family of 2 members putatively forms cation-selective ion channels. They are predicted to contain two KV-style six-transmembrane domains, suggesting they form a dimer in the membrane. These channels are related to catsper channels channels and, more distantly, TRP channels.
  • Light-gated channels like channelrhodopsin are directly opened by the action of light.

Sodium channels (also known as voltage-gated sodium channels) are integral membrane proteins that are localized in and conduct sodium ions (Na+) through a cells plasma membrane. ... Voltage-gated ion channel is a ion channel that is specifically activated, or gated, by the surrounding potential difference near the channel (or near the cell, neuron or synapse). ... This article or section is in need of attention from an expert on the subject. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... The general structure of an α-amino acid molecule, with the amine group on the left and the carboxyl group on the right. ... Glycosylation is the process or result of addition of saccharides to proteins and lipids. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Voltage-gated ion channel is a ion channel that is specifically activated, or gated, by the surrounding potential difference near the channel (or near the cell, neuron or synapse). ... This article or section is in need of attention from an expert on the subject. ... In cell biology, potassium channels are the most common type of ion channel. ... Voltage-gated potassium channel are a family of voltage gated potassium channels. ... Voltage-gated ion channel is a ion channel that is specifically activated, or gated, by the surrounding potential difference near the channel (or near the cell, neuron or synapse). ... This article or section is in need of attention from an expert on the subject. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... A tetramer is a protein with four subunits (tetrameric). ... Calcium-activated potassium channels: This family of ion channels is, for the most part, activated by intracellular Ca2+ and contains 8 members. ... Inwardly rectifing potassium channels (Kir or IRK) are potassium selective ion channels. ... ATP may refer to: Chemistry/Biochemistry Adenosine triphosphate, the universal energy currency of all living organisms Companies Alberta Theatre Projects, a major Canadian theatre company. ... G-proteins, short for guanine nucleotide binding proteins, are a family of proteins involved in second messenger cascades. ... Two-pore-domain potassium channels: This family of 15 members form what is known as leak channels, and they follow Goldman-Hodgkin-Katz (open) rectification. ... Resting channels are ion channels in the plasma membrane of a cell that remain open at all times. ... The Goldman-Hodgkin-Katz current equation (or GHK current equation) describes the current carried by an ionic species across a cell membrane as a function of the transmembrane potential and the concentrations of the ion inside and outside of the cell. ... AC, half-wave and full wave rectified signals A rectifier is an electrical device, comprising one or more semiconductive devices (such as diodes) or vacuum tubes arranged for converting alternating current to direct current. ... Ion channels are present in the membranes that surround all biological cells. ... There is a real need to make clear to what transient refers in a transient receptor potential, and the advice of the wider community is solicited to fill this need. ... Type Species Musca funebris Fabricius, 1787 Drosophila is a genus of small flies whose members are often called small fruit flies, or more appropriately vinegar flies, wine flies, pomace flies, grape flies, and picked fruit-flies. ... Voltage-gated ion channel is a ion channel that is specifically activated, or gated, by the surrounding potential difference near the channel (or near the cell, neuron or synapse). ... Stretch-activated or stretch-gated ion channels are ion channels which open their pores in response to mechanical deformation of a neurons plasma membrane. ... Lake Tahoe The Tahoe Regional Planning Agency (or TRPA) was formed in 1969 through a bi-state compact between California and Nevada which was ratified by the U.S. Congress. ... A Cyclic nucleotide-gated ion channel is any ion channel that opens in the presence of cyclic nucleotides. ... Camp may mean: Gatherings of people: Campsite Temporary settlement of a band of foragers. ... Cyclic guanosine monophosphate (cGMP) is a second messenger derived from GTP. Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). ... Voltage-gated ion channel is a ion channel that is specifically activated, or gated, by the surrounding potential difference near the channel (or near the cell, neuron or synapse). ... In biology, hyperpolarization is any change in a cells membrane potential that makes it more polarized. ... Camp may mean: Gatherings of people: Campsite Temporary settlement of a band of foragers. ... Cyclic guanosine monophosphate (cGMP) is a second messenger derived from GTP. Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). ... The contractions of the heart are controlled by electrical impulses, these fire at a rate which controls the beat of the heart. ... The sinoatrial node (abbreviated SA node, also called the sinus node) is the impulse generating (pacemaker) tissue located in the right atrium of the heart. ... Cation channels of sperm: This small family of ion channels, normally referred to as Catsper channels or CatSper, is related to the two-pore channels and distantly related to TRP channels. ... Two-pore channels: This small family of 2 members putatively forms cation-selective ion channels. ... The phrase Transient receptor potential or TRP is appended to at least three classes of ion channels which mediate the response of a cell to external stimuli (electrical charge, substances, and forces) by increasing or decreasing its selective permeability to particular ions. ... Two-pore channels: This small family of 2 members putatively forms cation-selective ion channels. ... Cation channels of sperm: This small family of ion channels, normally referred to as Catsper channels or CatSper, is related to the two-pore channels and distantly related to TRP channels. ... There is a real need to make clear to what transient refers in a transient receptor potential, and the advice of the wider community is solicited to fill this need. ... Channelrhodopsins are ion channels that are directly opened by light. ... Ligand-gated ion channel is a broad term that refers to any ion channel that is gated (i. ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ... An acetylcholine receptor (abbreviated AChR) is an integral membrane protein that responds to the binding of the neurotransmitter acetylcholine. ... Glutamate is a neurotransmitter in nerve cells which binds to all glutamate receptors located on neuron membranes, and is an example of a transmembrane receptor. ... P2X receptors are a family of cation-permeable ligand gated ion channels that open in response to extracellular adenosine 5-triphosphate (ATP). ... The GABA receptors are a group of receptors with γ-aminobutyric acid (GABA) as their endogenous ligand. ...

Detailed structure

Channels differ with respect to the ion they let pass (for example, Na+, K+, Cl), the ways in which they may be regulated, the number of subunits of which they are composed and other aspects of structure. Channels belonging to the largest class, which includes the voltage-gated channels that underlie the nerve impulse, consists of four subunits with six transmembrane helices each. On activation, these helices move about and open the pore. Two of these six helices are separated by a loop that lines the pore and is the primary determinant of ion selectivity and conductance in this channel class and some others. The existence and mechanism for ion selectivity was first postulated in the 1960s by Clay Armstrong. The channel subunits of one such other class, for example, consist of just this "P" loop and two transmembrane helices. The determination of their molecular structure by Roderick MacKinnon using X-ray crystallography won a share of the 2003 Nobel Prize in Chemistry. Within an integral membrane protein, a transmembrane helix is a segment that is alpha-helical in structure, roughly 20 amino acids in length and (though it may be presumed to lie within the protein, out of contact with the surrounding lipid bilayer) is said to span the membrane. ... Clay Armstrong is a prominent physiologist and a former student of Dr. Andrew Fielding Huxley. ... Roderick MacKinnon (born 19 February 1956 in Burlington, Massachusetts) is a professor of Molecular Neurobiology and Biophysics at Rockefeller University who in 2003 was awarded the Nobel Prize in Chemistry for his work on the structure and operation of ion channels. ... Crystallography (from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and graphein = write) is the experimental science of determining the arrangement of atoms in solids. ... This is a list of Nobel Prize laureates in Chemistry from 1901 to 2006. ...


Because of their small size and the difficulty of crystallizing integral membrane proteins for X-ray analysis, it is only very recently that scientists have been able to directly examine what channels "look like." Particularly in cases where the crystallography required removing channels from their membranes with detergent, many researchers regard images that have been obtained as tentative. An example is the long-awaited crystal structure of a voltage-gated potassium channel, which was reported in May 2003. The detailed 3D structure of the magnesium channel from bacteria can be seen here. One inevitable ambiguity about these structures relates to the strong evidence that channels change conformation as they operate (they open and close, for example), such that the structure in the crystal could represent any one of these operational states. Most of what researchers have deduced about channel operation so far they have established through electrophysiology, biochemistry, gene sequence comparison and mutagenesis. Electrophysiology is the study of the electrical properties of biological cells and tissues. ... Biochemistry is the study of the chemical processes and transformations in living organisms. ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... This article is about mutation in biology, for other meanings see: mutation (disambiguation). ...


Diseases of Ion Channels

There are a number of chemicals and genetic disorders which disrupt normal functioning of ion channels and have disastrous consequences for the organism. Genetic disorders of ion channels and their modifiers are known as Channelopathies. See Category:Channelopathy for a full list. The chanellopathies are human diseases linked to mutations in genes coding for ion channel subunits or proteins that regulate them. ...


Chemicals

Genetic Tetrodotoxin (anhydrotetrodotoxin 4-epitetrodotoxin, tetrodonic acid, TTX) is a potent neurotoxin, which blocks action potentials in nerves by binding to the pores of the voltage-gated sodium channels in nerve cell membranes. ... Genera Amblyrhynchotes Arothron Auriglobus Canthigaster Carinotetraodon Chelonodon Colomesus Contusus Ephippion Feroxodon Fugu Gastrophysus Javichthys Lagocephalus Liosaccus Marilyna Monotretus Omegaphora Pelagocephalus Polyspina Reicheltia Sphoeroides Takifugu Tetractenos Tetraodon Torquigener Tylerius Xenopterus The pufferfish, also called blowfish, swellfish, balloonfish are fish making up the family Tetraodontidae, within the order Tetraodontiformes. ... smooth newt Newts are small, usually bright-coloured semiaquatic salamanders of North America, Europe and North Asia. ... Saxitoxin (STX) is a neurotoxin found in marine dinoflagellates (algae). ... Classes Dinophyceae Noctiluciphyceae Syndiniophyceae The dinoflagellates are a large group of flagellate protists. ... A red tide off the coast of La Jolla, California. ... A conotoxin is one of a group of neurotoxic peptides isolated from the venom of the marine cone snail. ... Genera Asprella Chelyconus Conus Floraconus Leptoconus The cone snails or cone shells (Conidae) are marine snails found in coral reefs. ... Lidocaine (INN) (IPA: ) or lignocaine (former BAN) (IPA: ) is a common local anesthetic and antiarrhythmic drug. ... Procaine hydrochloride is a local anesthetic used primarily in dentistry. ... Wikipedia does not yet have an article with this exact name. ... Dendrotoxins are a class of neurotoxins produced by mamba snakes that block potassium channels thereby enhancing the release of acetylcholine. ... Species - Eastern green mamba - Jamesons mamba - Black mamba - Western green mamba For other uses, see Mamba (disambiguation). ... Families Acrochordidae Aniliidae Anomalepididae Anomochilidae Atractaspididae Boidae Bolyeriidae Colubridae Cylindrophiidae Elapidae Hydrophiidae Leptotyphlopidae Loxocemidae Pythonidae Tropidophiidae Typhlopidae Uropeltidae Viperidae Xenopeltidae Snakes are cold blooded legless reptiles closely related to lizards, which share the order Squamata. ...

The Shaker (Sh) gene, when mutated, causes a variety of atypical behaviors in the fruit fly, Drosophila melanogaster. ... Hyperkalaemic periodic paralysis is a genetic disorder which occurs in both humans and horses. ... Hyperkalaemic periodic paralysis is a genetic disorder which occurs in both humans and horses. ... Paramyotonia congenita is a rare congenital neuromuscular disorder which is characterized by a condition in which the muscles do not relax after contracting (myotonia). ... Generalized epilepsy with febrile seizures plus (GEFS+) is a syndromic autosomal dominant disorder where afflicted individuals can exhibit numerous epilepsy phenotypes. ... It has been suggested that Episodic Ataxia Type-1 be merged into this article or section. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The long QT syndrome (LQTS) is a heart disease in which there is an abnormally long delay between the electrical excitation (or depolarization) and relaxation (repolarization) of the ventricles of the heart. ... In the heart, a ventricle is a heart chamber which collects blood from an atrium (another heart chamber that is smaller than ventricle) and pumps it out of the heart. ... A cardiac arrhythmia, also called cardiac dysrhythmia, is a disturbance in the regular rhythm of the heartbeat. ... In medicine, the term syndrome is the association of several clinically recognizable features, signs, symptoms, phenomena or characteristics which often occur together, so that the presence of one feature alerts the physician to the presence of the others. ... In biology, mutations are changes to the genetic material (either DNA or RNA). ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... In cell biology, potassium channels are the most common type of ion channel. ... In neuroscience, repolarization refers to the change in membrane potential that returns the membrane potential to a negative value after the depolarization phase of an action potential has just previously changed the membrane potential to a positive value. ... The Brugada syndrome is a genetic disease that is manifest by abnormal electrocardiogram (ECG) findings and an increased risk of sudden cardiac death. ... Sodium channels (also known as voltage-gated sodium channels) are integral membrane proteins that are localized in and conduct sodium ions (Na+) through a cells plasma membrane. ...

History

The existence of ion channels was hypothesized by the British biophysicists Alan Hodgkin and Andrew Huxley as part of their Nobel Prize-winning theory of the nerve impulse, published in 1952. The existence of ion channels was confirmed in the 1970s with an electrical recording technique known as the "patch clamp," which led to a Nobel Prize to Erwin Neher and Bert Sakmann, the technique's inventors. Hundreds if not thousands of researchers continue to pursue a more detailed understanding of how these proteins work. In recent years the development of automated patch clamp devices helped to increase the throughput in ion channel screening significantly. Biophysics (also biological physics) is an interdisciplinary science that applies the theories and methods of physics, to questions of biology. ... Sir Alan Lloyd Hodgkin (February 5, 1914 _ December 20, 1998) was a British physiologist and biophysicist, who won the 1963 Nobel Prize in Physiology or Medicine for his work with Andrew Fielding Huxley on the basis of nerve action potentials, the electrical impulses that enable the activity of an... Andrew Huxley at Trinity College, Cambridge, July 2005 Family tree Sir Andrew Fielding Huxley, OM, FRS (born 22 November 1917, Hampstead, London, England, UK) is a British physiologist and biophysicist, who won the 1963 Nobel Prize in Physiology or Medicine for his work with Alan Lloyd Hodgkin on the basis... List of Nobel Prize laureates in Physiology or Medicine from 1901 to the present day. ... Schematic of an electrophysiological recording of an action potential showing the various phases which occur as the wave passes a point on a cell membrane. ... The 1970s decade refers to the years from 1970 to 1979, inclusive. ... Electrophysiology is the study of the electrical properties of biological cells and tissues. ... Patch clamp technique is technique in electrophysiology that allows the study of individual ion channels in cells. ... Erwin Neher (born 1944 in Landsberg am Lech, Bavaria) is a German biologist. ... Bert Sakmann (born June 12, 1942) is a German cell physiologist. ... Electrophysiology is the study of the electrical properties of biological cells and tissues. ...


The Nobel Prize in chemistry for 2003 was awarded to two American scientist; to Roderick MacKinnon for his studies on the physico-chemical properties of ion channel function, including x-ray crystallographic structure studies; and to Peter Agre for his similar work on aquaporins. Roderick MacKinnon (born 19 February 1956 in Burlington, Massachusetts) is a professor of Molecular Neurobiology and Biophysics at Rockefeller University who in 2003 was awarded the Nobel Prize in Chemistry for his work on the structure and operation of ion channels. ... X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of X-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ... Proteins are amino acid chains, made up from 20 different L-α-amino acids, also referred to as residues, that fold into unique three-dimensional protein structures. ... Peter Agre (born January 30, 1949) is an American biologist who was awarded the 2003 Nobel Prize in Chemistry (which he shared with Roderick MacKinnon) for his discovery of aquaporins. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...


Reference:

References

  1. ^ Two textbooks that discuss ion channels are: Neuroscience (2nd edition) Dale Purves, George J. Augustine, David Fitzpatrick, Lawrence. C. Katz, Anthony-Samuel LaMantia, James O. McNamara, S. Mark Williams, editors. Published by Sinauer Associates, Inc. (2001) online textbook and Basic Neurochemistry: Molecular, Cellular, and Medical Aspects (6th edition) by George J Siegel, Bernard W Agranoff, R. W Albers, Stephen K Fisher and Michael D Uhler published by Lippincott, Williams & Wilkins (1999): online textbook

Dr. Bertil Hille is an American biologist. ...

See also

A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... This article or section does not cite its references or sources. ... The chanellopathies are human diseases linked to mutations in genes coding for ion channel subunits or proteins that regulate them. ... It has been suggested that Neurotoxicity be merged into this article or section. ... This page links directly from the magnesium in biological systems page. ... Passive transport is a means of moving biochemicals, and other atomic or molecular substances, across membranes. ... Transmembrane receptors are integral membrane proteins, which reside and operate typically within a cells plasma membrane, but also in the membranes of some subcellular compartments and organelles. ...

External links


  Results from FactBites:
 
Ligand-Gated Ion Channel Database (663 words)
Ligand-Gated Ion Channels are transmembrane proteins that can exist under different conformations, at least one forming a pore through the membrane connecting the two neighbour compartments.
The equilibrium between the various conformations is affected by the binding of ligands on the channels.
The ATP gated channels (ATP2x receptors) are made of three homologous subunits, each with two transmembrane segments.
  More results at FactBites »

 
 

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