Document Detail

Does the KdpA subunit from the high affinity K(+)-translocating P-type KDP-ATPase have a structure similar to that of K(+) channels?
MedLine Citation:
PMID:  10620285     Owner:  NLM     Status:  MEDLINE    
Evidence is presented that the transmembrane KdpA subunit of the high affinity K(+)-translocating P-type Kdp-ATPase is evolutionarily derived from the superfamily of 2TM-type K(+) channels in bacteria. This extends a previous study relating the K(+) channels to the KtrAB, Trk, Trk1,2, and HKT1 K(+) symporter superfamily of both prokaryotes and eukaryotes. Although the channels are formed by four single-MPM motif subunits, the transmembrane KdpA subunit and the transmembrane subunit of the symporter proteins are postulated to have four corresponding MPM motifs within a single sequence. Analysis of 17 KdpA sequences reveals a pattern of residue conservation similar to that of the symporters and channels, and consistent with the crystal structure of the KcsA K(+) channel. In addition, the most highly conserved residues between the families, specifically the central glycines of the P2 segments, are those previously identified as crucial for the property of K(+)-selectivity that is common to each protein. This hypothesis is consistent with an experimental study of mutations that alter K(+) binding affinity of the Kdp transporter. Although most of the results of a previous study of the transmembrane topology of KdpA are consistent with the 4-MPM model, the one deviation can be explained by a plausible change in the structure due to the experimental method.
S R Durell; E P Bakker; H R Guy
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biophysical journal     Volume:  78     ISSN:  0006-3495     ISO Abbreviation:  Biophys. J.     Publication Date:  2000 Jan 
Date Detail:
Created Date:  2000-02-14     Completed Date:  2000-02-14     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0370626     Medline TA:  Biophys J     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  188-99     Citation Subset:  IM; S    
Laboratory of Experimental Biology, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892-5677, USA.
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MeSH Terms
Adenosine Triphosphatases / chemistry*,  metabolism
Amino Acid Sequence
Bacterial Proteins / chemistry
Carrier Proteins / chemistry*,  metabolism
Cation Transport Proteins*
Cell Membrane / ultrastructure
Conserved Sequence
Databases as Topic
Escherichia coli Proteins*
Evolution, Molecular
Macromolecular Substances
Models, Molecular
Molecular Sequence Data
Peptide Library
Potassium / metabolism
Potassium Channels / chemistry*
Protein Structure, Quaternary
Protein Structure, Secondary
Sequence Alignment
Sequence Homology, Amino Acid
Reg. No./Substance:
0/Bacterial Proteins; 0/Carrier Proteins; 0/Cation Transport Proteins; 0/Escherichia coli Proteins; 0/Macromolecular Substances; 0/Peptide Library; 0/Potassium Channels; 7440-09-7/Potassium; EC 3.6.1.-/Adenosine Triphosphatases; EC 3.6.1.-/potassium translocating Kdp-ATPase, E coli

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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