TY - JOUR
T1 - Crystal structure of a potassium ion transporter, TrkH
AU - Cao, Yu
AU - Jin, Xiangshu
AU - Huang, Hua
AU - Derebe, Mehabaw Getahun
AU - Levin, Elena J.
AU - Kabaleeswaran, Venkataraman
AU - Pan, Yaping
AU - Punta, Marco
AU - Love, James
AU - Weng, Jun
AU - Quick, Matthias
AU - Ye, Sheng
AU - Kloss, Brian
AU - Bruni, Renato
AU - Martinez-Hackert, Erik
AU - Hendrickson, Wayne A.
AU - Rost, Burkhard
AU - Javitch, Jonathan A.
AU - Rajashankar, Kanagalaghatta R.
AU - Jiang, Youxing
AU - Zhou, Ming
N1 - Funding Information:
Acknowledgements Data for this study were measured at beamlines X4A, X4C, X25 and X29 of the National Synchrotron Light Source and the NE-CAT 24ID-C and E at the Advanced Photon Source. This work was supported by the U.S. National Institutes of Health (grants HL086392, DK088057 and GM05026-sub0007 to M.Z.) and the American Heart Association (0630148N to M.Z.). M.Z is a Pew Scholar in Biomedical Sciences. The New York Consortium on Membrane Protein Structure central facility is supportedbygrant GM05026toW.A.H.aspartofthe ProteinStructureInitiative(PSI-2) establishedbythe NationalInstitute ofGeneral Medical Sciences.WethankB.Honig for support, K. Jung for providing E. coli LB650, and J. Morais-Cabral, S.-Y. Lee, H. R. Guy, C.L.Slaymanand E.P.Bakkerfor discussionsand comments onthe manuscript.M.Z.is grateful to R. MacKinnon for advice and support throughout the project.
PY - 2011/3/17
Y1 - 2011/3/17
N2 - 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.
AB - 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.
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U2 - 10.1038/nature09731
DO - 10.1038/nature09731
M3 - Article
C2 - 21317882
AN - SCOPUS:79952818073
SN - 0028-0836
VL - 471
SP - 336
EP - 341
JO - Nature
JF - Nature
IS - 7338
ER -