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PDBsum entry 4bgc
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Transport protein
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PDB id
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4bgc
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References listed in PDB file
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Key reference
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Title
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1.2 Å X-Ray structure of the renal potassium channel kv1.3 t1 domain.
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Authors
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W.Kremer,
M.Weyand,
A.Winklmeier,
C.Schreier,
H.R.Kalbitzer.
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Ref.
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Protein J, 2013,
32,
533-542.
[DOI no: ]
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PubMed id
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Abstract
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Here we present the structure of the T1 domain derived from the
voltage-dependent potassium channel Kv1.3 of Homo sapiens sapiens at 1.2 Å
resolution crystallized under near-physiological conditions. The crystals were
grown without precipitant in 150 mM KPi, pH 6.25. The crystals show I4 symmetry
typical of the natural occurring tetrameric assembly of the single subunits. The
obtained structural model is based on the highest resolution currently achieved
for tetramerization domains of voltage-gated potassium channels. We identified
an identical fold of the monomer but inside the tetramer the single monomers
show a significant rotation which leads to a different orientation of the
tetramer compared to other known structures. Such a rotational movement inside
the tetrameric assembly might influence the gating properties of the channel. In
addition we see two distinct side chain configurations for amino acids located
in the top layer proximal to the membrane (Tyr109, Arg116, Ser129, Glu140,
Met142, Arg146), and amino acids in the bottom layer of the T1-domain distal
from the membrane (Val55, Ile56, Leu77, Arg86). The relative populations of
these two states are ranging from 50:50 for Val55, Tyr109, Arg116, Ser129,
Glu140, 60:40 for Met142, 65:35 for Arg86, 70:30 for Arg146, and 80:20 for Ile56
and Leu77. The data suggest that in solution these amino acids are involved in
an equilibrium of conformational states that may be coupled to the functional
states of the whole potassium channel.
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