for I am fearfully and wonderfully made:
Psalm 139:14
"A paper in Nature describes for the first time a detailed description of one of the cell’s chloride channels, complex pores in the cell membrane that allow negative ions like Cl– from table salt to pass through, but restrict others. (For a good layman’s summary and illustration, see this news release on the Howard Hughes Medical Institute website.)
The full text of the paper reveals these channels to be “amazingly different” than cation channels (those that allow positively charged ions), and are shown to be exquisite protein complexes with gates composed of negatively-charged tips (that would normally repulse chloride ions) that apparently swing out of the way to let the desired molecules in. The authors explain the importance of these chloride channels:
The precise placement of charged ends of amino acids along the pore attracts the chloride ions down the channel, without being so attractive that the ions would bind to them and get stuck.
"A paper in Nature describes for the first time a detailed description of one of the cell’s chloride channels, complex pores in the cell membrane that allow negative ions like Cl– from table salt to pass through, but restrict others. (For a good layman’s summary and illustration, see this news release on the Howard Hughes Medical Institute website.)
Thomas Jentsch describes this as another “spectacular breakthrough” by Roderick MacKinnon’s team. He opens with an explanation:
“Ion channels are proteins with a seemingly simple task – to allow the passive flow of ions across biological membranes. But this process requires more sophistication than one would imagine.”
The full text of the paper reveals these channels to be “amazingly different” than cation channels (those that allow positively charged ions), and are shown to be exquisite protein complexes with gates composed of negatively-charged tips (that would normally repulse chloride ions) that apparently swing out of the way to let the desired molecules in. The authors explain the importance of these chloride channels:
"Potassium, sodium, calcium and chloride ions are used ingeniously by living systems in the performance of fundamental cellular tasks. Through the action of ion pumps, a large fraction of a cell’s metabolic energy is spent establishing transmembrane ion gradients. These gradients, through the action of ion channels, are used to produce electrical signals, activate signal transduction pathways, regulate cell volume, and mediate fluid and electrolyte transport. To carry out these tasks, an ion channel has to be selective, that is, permit only certain ionic species to flow through its pore."
The precise placement of charged ends of amino acids along the pore attracts the chloride ions down the channel, without being so attractive that the ions would bind to them and get stuck.
--Failure of these channels is implicated in some serious muscle and kidney diseases.
Some animals have such a multitude of these effective ion pumps,they can generate a powerful electric shock.
Says Jentsch: “On the basis of elegant biophysical studies by Miller and White, who showed that the electric ray Torpedo contains large amounts of a peculiar anion channel, the first voltage-gated Cl– channel was cloned by my group in 1990. We named it ClC-0, as we assumed that it would found a family of Cl– channels. This turned out to be true: CLC channels are found in all kingdoms of life, with humans alone having nine different CLC genes.”
The electric ray can generate 200 volts. On another related front, EurekAlert reported the next day that the UMass scientists have found microbes on the bottom of the sea that generate electricity, and the Navy is interested in harvesting these microorganisms to create living batteries."
The electric ray can generate 200 volts. On another related front, EurekAlert reported the next day that the UMass scientists have found microbes on the bottom of the sea that generate electricity, and the Navy is interested in harvesting these microorganisms to create living batteries."
CEH