TY - JOUR
T1 - Protein interactions central to stabilizing the K + channel selectivity filter in a four-sited configuration for selective K + permeation
AU - Sauer, David B.
AU - Zenga, Weizhong
AU - Raghunathan, Srinivasan
AU - Jiang, Youxing
PY - 2011/10/4
Y1 - 2011/10/4
N2 - The structural and functional conversion of the nonselective NaK channel to a K + selective channel (NaK2K) allows us to identify two key residues, Tyr and Asp in the filter sequence of TVGYGD, that participate in interactions central to stabilizing the K + channel selectivity filter. By using protein crystallography and channel electrophysiology, we demonstrate that the K + channel filter exists as an energetically strained structure and requires these key protein interactions working in concert to hold the filter in the precisely defined four-sited configuration that is essential for selective K +permeation. Disruption of either interaction, as tested on both the NaK2K and eukaryotic K v1.6 channels, can reduce or completely abolish K + selectivity and in some cases may also lead to channel inactivation due to conformational changes at the filter. Additionally, on the scaffold of NaK we recapitulate the protein interactions found in the filter of the Kir channel family, which uses a distinct interaction network to achieve similar stabilization of the filter.
AB - The structural and functional conversion of the nonselective NaK channel to a K + selective channel (NaK2K) allows us to identify two key residues, Tyr and Asp in the filter sequence of TVGYGD, that participate in interactions central to stabilizing the K + channel selectivity filter. By using protein crystallography and channel electrophysiology, we demonstrate that the K + channel filter exists as an energetically strained structure and requires these key protein interactions working in concert to hold the filter in the precisely defined four-sited configuration that is essential for selective K +permeation. Disruption of either interaction, as tested on both the NaK2K and eukaryotic K v1.6 channels, can reduce or completely abolish K + selectivity and in some cases may also lead to channel inactivation due to conformational changes at the filter. Additionally, on the scaffold of NaK we recapitulate the protein interactions found in the filter of the Kir channel family, which uses a distinct interaction network to achieve similar stabilization of the filter.
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U2 - 10.1073/pnas.1111688108
DO - 10.1073/pnas.1111688108
M3 - Article
C2 - 21933962
AN - SCOPUS:80053638085
SN - 0027-8424
VL - 108
SP - 16634
EP - 16639
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 40
ER -