6S5C

Square conformation of KtrA WT ring with bound ATP and calcium

Summary for 6S5C

• Entry DOI: 10.2210/pdb6s5c/pdb
• Related: 6S2J 6S5B
• Descriptor: Ktr system potassium uptake protein A, ADENOSINE-5'-TRIPHOSPHATE, CALCIUM ION (3 entities in total)
• Functional Keywords: rck domain, potassium homeostasis, cation channel, calcium, square conformation octameric ring, atp, transport protein
• Biological source: Bacillus subtilis subsp. subtilis str. 168
• Total number of polymer chains: 2
• Total formula weight: 50887.96

Authors

Teixeira-Duarte, C.M.,Fonseca, F.,Morais-Cabral, J.H. (deposition date: 2019-07-01, release date: 2020-01-08, Last modification date: 2024-01-24)

Primary citation

Teixeira-Duarte, C.M.,Fonseca, F.,Morais Cabral, J.H.
Activation of a nucleotide-dependent RCK domain requires binding of a cation cofactor to a conserved site.
Elife, 8:-, 2019

PubMed Abstract: RCK domains regulate the activity of K channels and transporters in eukaryotic and prokaryotic organisms by responding to ions or nucleotides. The mechanisms of RCK activation by Ca in the eukaryotic BK and bacterial MthK K channels are well understood. However, the molecular details of activation in nucleotide-dependent RCK domains are not clear. Through a functional and structural analysis of the mechanism of ATP activation in KtrA, a RCK domain from the KtrAB cation channel, we have found that activation by nucleotide requires binding of cations to an intra-dimer interface site in the RCK dimer. In particular, divalent cations are coordinated by the γ-phosphates of bound-ATP, tethering the two subunits and stabilizing the active state conformation. Strikingly, the binding site residues are highly conserved in many different nucleotide-dependent RCK domains, indicating that divalent cations are a general cofactor in the regulatory mechanism of many nucleotide-dependent RCK domains.

PubMed: 31868587
DOI: 10.7554/eLife.50661

Experimental method

X-RAY DIFFRACTION (3 Å)