Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Biophys J
1995 Mar 01;683:900-5. doi: 10.1016/S0006-3495(95)80266-3.
Show Gene links
Show Anatomy links
Side-chain accessibilities in the pore of a K+ channel probed by sulfhydryl-specific reagents after cysteine-scanning mutagenesis.
Kürz LL
,
Zühlke RD
,
Zhang HJ
,
Joho RH
.
???displayArticle.abstract???
To gain insight into the secondary structure of the ion conduction pathway of a voltage-gated K+ channel, we used sulfhydryl-specific reagents of different diameters to probe amino acid side-chain accessibilities in the pore of the channel after cysteine-substitution mutagenesis. We identified five positions at which modified amino acid side chains are accessible from the aqueous lumen of the external channel vestibule. Covalent coupling of the 2-trimethylammonium-thioethyl group to cysteine thiols leads to position-dependent current reduction, suggesting a gradual narrowing of the pore. The fact that the modified side chains of two adjacent amino acids are reactive is not compatible with the ion conduction pathway forming a regular beta-pleated sheet at these positions. The smaller thiol reagent Cd2+ reacts with modified side chains that are also accessible to the larger (2-trimethylammoniumethyl)methanethiosulfate (MTSET) [corrected]. Our results imply that the outer vestibule of a potassium-selective ion channel narrows over a short distance of three amino acids near a position where a regular beta-structure is unlikely.
Akabas,
Acetylcholine receptor channel structure probed in cysteine-substitution mutants.
1992,
Pubmed
,
Xenbase
Bogusz,
Is a beta-barrel model of the K+ channel energetically feasible?
1992,
Pubmed
Catterall,
Structure and function of voltage-gated ion channels.
1993,
Pubmed
Choi,
The internal quaternary ammonium receptor site of Shaker potassium channels.
1993,
Pubmed
,
Xenbase
De Biasi,
Histidine substitution identifies a surface position and confers Cs+ selectivity on a K+ pore.
1993,
Pubmed
Durell,
Atomic scale structure and functional models of voltage-gated potassium channels.
1992,
Pubmed
Frech,
A novel potassium channel with delayed rectifier properties isolated from rat brain by expression cloning.
1989,
Pubmed
,
Xenbase
Hartmann,
Exchange of conduction pathways between two related K+ channels.
1991,
Pubmed
,
Xenbase
Heginbotham,
A functional connection between the pores of distantly related ion channels as revealed by mutant K+ channels.
1992,
Pubmed
,
Xenbase
Heginbotham,
The aromatic binding site for tetraethylammonium ion on potassium channels.
1992,
Pubmed
Jan,
Tracing the roots of ion channels.
1992,
Pubmed
Kavanaugh,
Interaction between tetraethylammonium and amino acid residues in the pore of cloned voltage-dependent potassium channels.
1991,
Pubmed
,
Xenbase
Kavanaugh,
Multiple subunits of a voltage-dependent potassium channel contribute to the binding site for tetraethylammonium.
1992,
Pubmed
,
Xenbase
Kirsch,
Differences between the deep pores of K+ channels determined by an interacting pair of nonpolar amino acids.
1992,
Pubmed
,
Xenbase
Kirsch,
A single nonpolar residue in the deep pore of related K+ channels acts as a K+:Rb+ conductance switch.
1992,
Pubmed
Lopez,
Evidence that the S6 segment of the Shaker voltage-gated K+ channel comprises part of the pore.
1994,
Pubmed
,
Xenbase
MacKinnon,
Mutations affecting TEA blockade and ion permeation in voltage-activated K+ channels.
1990,
Pubmed
Slesinger,
The S4-S5 loop contributes to the ion-selective pore of potassium channels.
1993,
Pubmed
,
Xenbase
Stauffer,
Electrostatic potential of the acetylcholine binding sites in the nicotinic receptor probed by reactions of binding-site cysteines with charged methanethiosulfonates.
1994,
Pubmed
VanDongen,
Alteration and restoration of K+ channel function by deletions at the N- and C-termini.
1990,
Pubmed
Yellen,
An engineered cysteine in the external mouth of a K+ channel allows inactivation to be modulated by metal binding.
1994,
Pubmed
Yellen,
Mutations affecting internal TEA blockade identify the probable pore-forming region of a K+ channel.
1991,
Pubmed
Yool,
Alteration of ionic selectivity of a K+ channel by mutation of the H5 region.
1991,
Pubmed
,
Xenbase
Zühlke,
Role of an invariant cysteine in gating and ion permeation of the voltage-sensitive K+ channel Kv2.1.
1994,
Pubmed
,
Xenbase