KTN (RCK) domains are nucleotide-binding folds that form the cytoplasmic regulatory complexes of various K+ channels and transporters. The mechanisms these proteins use to control their transmembrane pore-forming counterparts remains unclear despite numerous electrophysiological and structural studies. KTN (RCK) domains consistently crystallize as dimers within the asymmetric unit, forming a pronounced hinge between two Rossmann folds. We have previously proposed that modification of the hinge angle plays an important role in activating the associated membrane-integrated components of the channel or transporter. Here we report the structure of the C-terminal, KTN-bearing domain of the E. coli KefC K+ efflux system in association with the ancillary subunit, KefF, which is known to stabilize the conductive state. The structure of the complex and functional analysis of KefC variants reveal that control of the conformational flexibility inherent in the KTN dimer hinge is modulated by KefF and essential for regulation of KefC ion flux.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2920069 | PMC |
| http://dx.doi.org/10.1016/j.str.2009.03.018 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The Potassium Efflux System Kef: Bacterial Protection against Toxic Electrophilic Compounds.
Membranes (Basel)
April 2023
Rudolf Virchow Center and Biocenter, Institute of Biochemistry II, Julius-Maximilians-Universität Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany.
Kef couples the potassium efflux with proton influx in gram-negative bacteria. The resulting acidification of the cytosol efficiently prevents the killing of the bacteria by reactive electrophilic compounds. While other degradation pathways for electrophiles exist, Kef is a short-term response that is crucial for survival.
View Article and Find Full Text PDFHow RCK domains regulate gating of K+ channels.
Biol Chem
September 2019
Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, D-60438 Frankfurt Main, Germany.
Potassium channels play a crucial role in the physiology of all living organisms. They maintain the membrane potential and are involved in electrical signaling, pH homeostasis, cell-cell communication and survival under osmotic stress. Many prokaryotic potassium channels and members of the eukaryotic Slo channels are regulated by tethered cytoplasmic domains or associated soluble proteins, which belong to the family of regulator of potassium conductance (RCK).
View Article and Find Full Text PDFKTN (RCK) domains regulate K+ channels and transporters by controlling the dimer-hinge conformation.
Structure
June 2009
Drug Development Department, Nevada Cancer Institute, Las Vegas, NV 89135, USA.
KTN (RCK) domains are nucleotide-binding folds that form the cytoplasmic regulatory complexes of various K+ channels and transporters. The mechanisms these proteins use to control their transmembrane pore-forming counterparts remains unclear despite numerous electrophysiological and structural studies. KTN (RCK) domains consistently crystallize as dimers within the asymmetric unit, forming a pronounced hinge between two Rossmann folds.
View Article and Find Full Text PDFThree two-component transporters with channel-like properties have monovalent cation/proton antiport activity.
Proc Natl Acad Sci U S A
August 2007
Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, NY 10029, USA.
Properties of four two-component bacterial transport systems of the cation/proton antiporter-2 (CPA2) family led to suggestions that this CPA2 subset may use a channel rather than an antiport mechanism [see Booth IR, Edwards MD, Gunasekera B, Li C, Miller S (2005) in Bacterial Ion Channels, eds Kubalski A, Martinac B (Am Soc Microbiol, Washington, DC), pp 21-40]. The transporter subset includes the intensively studied glutathione-gated K(+) efflux systems from Escherichia coli, KefGB, and KefFC. KefG and KefF are ancillary proteins.
View Article and Find Full Text PDFATP binding to the KTN/RCK subunit KtrA from the K+ -uptake system KtrAB of Vibrio alginolyticus: its role in the formation of the KtrAB complex and its requirement in vivo.
J Biol Chem
May 2007
Department of Microbiology, University of Osnabrück, Osnabrück, Germany.
Subunit KtrA of the bacterial Na(+)-dependent K(+)-translocating KtrAB systems belongs to the KTN/RCK family of regulatory proteins and protein domains. They are located at the cytoplasmic side of the cell membrane. By binding ligands they regulate the activity of a number of K(+) transporters and K(+) channels.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!