3eyw
From Proteopedia
Crystal structure of the C-terminal domain of E. coli KefC in complex with KefF
Structural highlights
FunctionKEFC_ECOLI Transport system that facilitates potassium-efflux, possibly by potassium-proton antiport.KEFF_ECOLI Regulatory subunit of a potassium efflux system that confers protection against electrophiles. Required for full activity of KefC. Shows redox enzymatic activity, but this enzymatic activity is not required for activation of KefC. Can use a wide range of substrates, including electrophilic quinones, and its function could be to reduce the redox toxicity of electrophilic quinones in parallel with acting as triggers for the KefC efflux system.[HAMAP-Rule:MF_01414][1] [2] [3] Publication Abstract from PubMedKTN (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. KTN (RCK) domains regulate K+ channels and transporters by controlling the dimer-hinge conformation.,Roosild TP, Castronovo S, Miller S, Li C, Rasmussen T, Bartlett W, Gunasekera B, Choe S, Booth IR Structure. 2009 Jun 10;17(6):893-903. PMID:19523906[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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