Publication Date:
2013-04-20
Description:
In bacteria, archaea, fungi and plants the Trk, Ktr and HKT ion transporters are key components of osmotic regulation, pH homeostasis and resistance to drought and high salinity. These ion transporters are functionally diverse: they can function as Na(+) or K(+) channels and possibly as cation/K(+) symporters. They are closely related to potassium channels both at the level of the membrane protein and at the level of the cytosolic regulatory domains. Here we describe the crystal structure of a Ktr K(+) transporter, the KtrAB complex from Bacillus subtilis. The structure shows the dimeric membrane protein KtrB assembled with a cytosolic octameric KtrA ring bound to ATP, an activating ligand. A comparison between the structure of KtrAB-ATP and the structures of the isolated full-length KtrA protein with ATP or ADP reveals a ligand-dependent conformational change in the octameric ring, raising new ideas about the mechanism of activation in these transporters.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vieira-Pires, Ricardo S -- Szollosi, Andras -- Morais-Cabral, Joao H -- England -- Nature. 2013 Apr 18;496(7445):323-8. doi: 10.1038/nature12055.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, Porto 4150-180, Portugal.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23598340" target="_blank"〉PubMed〈/a〉
Keywords:
Adenosine Diphosphate/metabolism
;
Adenosine Triphosphate/metabolism
;
Bacillus subtilis/*chemistry
;
Bacterial Proteins/*chemistry/*metabolism
;
Cation Transport Proteins/*chemistry/*metabolism
;
Crystallography, X-Ray
;
Ion Transport
;
Models, Biological
;
Models, Molecular
;
Potassium/*metabolism
;
Protein Conformation
;
Protein Subunits/chemistry/metabolism
;
Structure-Activity Relationship
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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