Publication Date:
2011-02-15
Description:
The TrkH/TrkG/KtrB proteins mediate K(+) uptake in bacteria and probably evolved from simple K(+) channels by multiple gene duplications or fusions. Here we present the crystal structure of a TrkH from Vibrio parahaemolyticus. TrkH is a homodimer, and each protomer contains an ion permeation pathway. A selectivity filter, similar in architecture to those of K(+) channels but significantly shorter, is lined by backbone and side-chain oxygen atoms. Functional studies showed that TrkH is selective for permeation of K(+) and Rb(+) over smaller ions such as Na(+) or Li(+). Immediately intracellular to the selectivity filter are an intramembrane loop and an arginine residue, both highly conserved, which constrict the permeation pathway. Substituting the arginine with an alanine significantly increases the rate of K(+) flux. These results reveal the molecular basis of K(+) selectivity and suggest a novel gating mechanism for this large and important family of membrane transport proteins.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077569/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077569/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cao, Yu -- Jin, Xiangshu -- Huang, Hua -- Derebe, Mehabaw Getahun -- Levin, Elena J -- Kabaleeswaran, Venkataraman -- Pan, Yaping -- Punta, Marco -- Love, James -- Weng, Jun -- Quick, Matthias -- Ye, Sheng -- Kloss, Brian -- Bruni, Renato -- Martinez-Hackert, Erik -- Hendrickson, Wayne A -- Rost, Burkhard -- Javitch, Jonathan A -- Rajashankar, Kanagalaghatta R -- Jiang, Youxing -- Zhou, Ming -- DK088057/DK/NIDDK NIH HHS/ -- GM05026/GM/NIGMS NIH HHS/ -- GM05026-SUB0007/GM/NIGMS NIH HHS/ -- HL086392/HL/NHLBI NIH HHS/ -- K05 DA022413/DA/NIDA NIH HHS/ -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 DK088057/DK/NIDDK NIH HHS/ -- R01 DK088057-01/DK/NIDDK NIH HHS/ -- R01 HL086392/HL/NHLBI NIH HHS/ -- R01 HL086392-05/HL/NHLBI NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2011 Mar 17;471(7338):336-40. doi: 10.1038/nature09731. Epub 2011 Feb 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology & Cellular Biophysics, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, New York 10032, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21317882" target="_blank"〉PubMed〈/a〉
Keywords:
ATP-Binding Cassette Transporters/chemistry
;
Amino Acid Sequence
;
Crystallography, X-Ray
;
Escherichia coli Proteins/chemistry
;
Ion Channel Gating
;
Ion Transport
;
Models, Molecular
;
Molecular Sequence Data
;
Potassium/metabolism
;
Potassium Channels/*chemistry/*metabolism
;
Structure-Activity Relationship
;
Substrate Specificity
;
Vibrio parahaemolyticus/*chemistry
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
