6I8V

KtrC with ATP bound


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.99 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.195 

Starting Model: experimental
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This is version 1.1 of the entry. See complete history


Literature

Characterization of the molecular properties of KtrC, a second RCK domain that regulates a Ktr channel in Bacillus subtilis.

Rocha, R.Teixeira-Duarte, C.M.Jorge, J.M.P.Morais-Cabral, J.H.

(2019) J Struct Biol 205: 34-43

  • DOI: https://doi.org/10.1016/j.jsb.2019.02.002
  • Primary Citation of Related Structures:  
    6I8V

  • PubMed Abstract: 

    RCK (regulating conductance of K + ) domains are common regulatory domains that control the activity of eukaryotic and prokaryotic K + channels and transporters. In bacteria these domains play roles in osmoregulation, regulation of turgor and membrane potential and in pH homeostasis. Whole-genome sequencing unveiled RCK gene redundancy, however the biological role of this redundancy is not well understood. In Bacillus subtilis, there are two closely related RCK domain proteins (KtrA and KtrC) that regulate the activity of the Ktr cation channels. KtrA has been well characterized but little is known about KtrC. We have characterized the structural and biochemical proprieties of KtrC and conclude that KtrC binds ATP and ADP, just like KtrA. However, in solution KtrC exist in a dynamic equilibrium between octamers and non-octameric species that is dependent on the bound ligand, with ATP destabilizing the octameric ring relative to ADP. Accordingly, KtrC-ADP crystal structures reveal closed octameric rings similar to those in KtrA, while KtrC-ATP adopts an open assembly with RCK domains forming a super-helix. In addition, both KtrC-ATP and -ADP octamers are stabilized by the signaling molecule cyclic-di-AMP, which binds to KtrC with high affinity. In contrast, c-di-AMP binds with 100-fold lower affinity to KtrA. Despite these differences we show with an E. coli complementation assay that KtrC and KtrA are interchangeable and able to form functional transporters with both KtrB and KtrD. The distinctive properties of KtrC, in particular ligand-dependent assembly/disassembly, suggest that this protein has a specific physiological role that is distinct from KtrA.


  • Organizational Affiliation

    i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Ktr system potassium uptake protein C221Bacillus subtilis subsp. subtilis str. 168Mutation(s): 0 
Gene Names: ktrCykqBylxVyzaCBSU14510
UniProt
Find proteins for P39760 (Bacillus subtilis (strain 168))
Explore P39760 
Go to UniProtKB:  P39760
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP39760
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.99 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.195 
  • Space Group: P 43 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.155α = 90
b = 84.155β = 90
c = 83.85γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
PortugalFLAD Proj. 34/2017 and 34/2018
PortugalFEDER POCI-01-0145-FEDER-029863
PortugalCompete2020
PortugalFCT PTDC/BIA-BQM/29863/2017

Revision History  (Full details and data files)

  • Version 1.0: 2019-10-30
    Type: Initial release
  • Version 1.1: 2024-01-24
    Changes: Data collection, Database references, Derived calculations, Refinement description