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PDBsum entry 1id1
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Membrane protein
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PDB id
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1id1
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Structure of the rck domain from the e. Coli k+ channel and demonstration of its presence in the human bk channel.
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Authors
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Y.Jiang,
A.Pico,
M.Cadene,
B.T.Chait,
R.Mackinnon.
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Ref.
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Neuron, 2001,
29,
593-601.
[DOI no: ]
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PubMed id
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Abstract
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The intracellular C-terminal domain structure of a six-transmembrane K+ channel
from Escherichia coli has been solved by X-ray crystallography at 2.4 A
resolution. The structure is representative of a broad class of domains/proteins
that regulate the conductance of K+ (here referred to as RCK domains) in
prokaryotic K+ transporters and K+ channels. The RCK domain has a Rossmann-fold
topology with unique positions, not commonly conserved among Rossmann-fold
proteins, composing a well-conserved salt bridge and a hydrophobic dimer
interface. Structure-based amino acid sequence alignments and mutational
analysis are used to demonstrate that an RCK domain is also present and is an
important component of the gating machinery in eukaryotic large-conductance Ca2+
activated K+ channels.
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Figure 1.
Figure 1. A Visual Argument for Channel Regulation by
C-Terminal Cytoplasmic Domains(A) Depiction of the aperture
formed by inner helices (red) of the tetrameric KcsA K^+ channel
with a nondescript C-terminal domain (gray).(B) Example
topologies of varied subfamilies of K^+ channels: (i)
prokaryotic K^+ channels with two transmembrane (TM) helices and
a putative NAD binding RCK domain (shaded); (ii) prokaryotic K^+
channels with six TM helices and an RCK domain (e.g., E. coli
Kch); (iii) eukaryotic large-conductance Ca^2+-activated K^+
channels (BK) with a homologous RCK domain and C-terminal Ca^2+
binding domain; (iv) eukaryotic small-conductance
Ca^2+-activated K^+ channels (SK) with a calmodulin binding
domain; (v) eukaryotic cyclic nucleotide–gated channels (CNG)
with a cNMP binding domain; and (vi) eukaryotic ATP-sensitive
inward rectifier K^+ channels (Kir6.1 and 6.2) with an ATP
binding domain
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Figure 4.
Figure 4. Comparison between the E. coli K^+ Channel RCK
Domain Dimer and the E. coli LIV Binding Protein(A) Stereo view
of the Cα trace of the E. coli K^+ channel RCK domain dimer.
Subunits are black and red.(B) Stereo view of the Cα trace of
the E. coli LIV binding protein
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The above figures are
reprinted
by permission from Cell Press:
Neuron
(2001,
29,
593-601)
copyright 2001.
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