Structures of KcsA in Complex with Symmetrical Quaternary Ammonium Compounds Reveal a Hydrophobic Binding Site
نویسندگان
چکیده
Potassium channels allow for the passive movement of potassium ions across the cell membrane and are instrumental in controlling the membrane potential in all cell types. Quaternary ammonium (QA) compounds block potassium channels and have long been used to study the functional and structural properties of these channels. Here we describe the interaction between three symmetrical hydrophobic QAs and the prokaryotic potassium channel KcsA. The structures demonstrate the presence of a hydrophobic pocket between the inner helices of KcsA and provide insight into the binding site and blocking mechanism of hydrophobic QAs. The structures also reveal a structurally hidden pathway between the central cavity and the outside membrane environment reminiscent of the lateral fenestration observed in sodium channels that can be accessed through small conformational changes in the pore wall. We propose that the hydrophobic binding pocket stabilizes the alkyl chains of long-chain QA molecules and may play a key role in hydrophobic drug binding in general.
منابع مشابه
In-silico Investigation of Tubulin Binding Modes of a Series of Novel Antiproliferative Spiroisoxazoline Compounds Using Docking Studies
Interference with microtubule polymerization results in cell cycle arrest leading to cell death. Colchicine is a well-known microtubule polymerization inhibitor which does so by binding to a specific site on tubulin. A set of 3',4'-bis (substituted phenyl)-4'H-spiro[indene-2,5'-isoxazol]-1(3H)-one derivatives with known antiproliferative activities were evaluated for their tubulin binding modes...
متن کاملIn-silico Investigation of Tubulin Binding Modes of a Series of Novel Antiproliferative Spiroisoxazoline Compounds Using Docking Studies
Interference with microtubule polymerization results in cell cycle arrest leading to cell death. Colchicine is a well-known microtubule polymerization inhibitor which does so by binding to a specific site on tubulin. A set of 3',4'-bis (substituted phenyl)-4'H-spiro[indene-2,5'-isoxazol]-1(3H)-one derivatives with known antiproliferative activities were evaluated for their tubulin binding modes...
متن کاملState-independent intracellular access of quaternary ammonium blockers to the pore of TREK-1
We previously reported that TREK-1 gating by internal pH and pressure occurs close to or within the selectivity filter. These conclusions were based upon kinetic measurements of high-affinity block by quaternary ammonium (QA) ions that appeared to exhibit state-independent accessibility to their binding site within the pore. Intriguingly, recent crystal structures of two related K2P potassium c...
متن کاملDibucaine inhibition of serum cholinesterase.
The dibucaine number (DN) was determined for serum cholinesterase (EC 3.1.1.8, SChE) in plasma samples. The ones with a DN of 79-82 were used, because they had the "usual" SChE variant. The enzyme was assayed colorimetrically by the reaction of 5,5'-dithiobis-[2-nitrobenzoic acid] (DTNB) with the free sulfhydryl groups of thiocholine that were produced by the enzyme reaction with butrylthiochol...
متن کاملCrystal Structure of the Substrate-Binding Domain from Listeria monocytogenes Bile-Resistance Determinant BilE
BilE has been reported as a bile resistance determinant that plays an important role in colonization of the gastrointestinal tract by Listeria monocytogenes, the causative agent of listeriosis. The mechanism(s) by which BilE mediates bile resistance are unknown. BilE shares significant sequence similarity with ATP-binding cassette (ABC) importers that contribute to virulence and stress response...
متن کامل