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PDBsum entry 3im5
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Signaling protein
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PDB id
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3im5
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References listed in PDB file
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Key reference
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Title
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Crystal structures of the n-Terminal domains of cardiac and skeletal muscle ryanodine receptors: insights into disease mutations.
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Authors
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P.A.Lobo,
F.Van petegem.
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Ref.
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Structure, 2009,
17,
1505-1514.
[DOI no: ]
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PubMed id
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Abstract
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Ryanodine receptors (RyRs) are channels governing the release of Ca(2+) from the
sarcoplasmic or endoplasmic reticulum. They are required for the contraction of
both skeletal (RyR1) and cardiac (RyR2) muscles. Mutations in both RyR1 and RyR2
have been associated with severe genetic disorders, but high-resolution data
describing the disease variants in detail have been lacking. Here we present the
crystal structures of the N-terminal domains of both RyR2 (1-217) and RyR1
(9-205) at 2.55 A and 2.9 A, respectively. The domains map in a hot spot region
for disease mutations. Both structures consist of a core beta trefoil domain
flanked by an alpha helix. Crystal structures of two RyR2 disease mutants, A77V
(2.2 A) and V186M (1.7 A), show that the mutations cause distinct local changes
in the surface of the protein. A RyR2 deletion mutant causes significant changes
in the thermal stability. The disease positions highlight two putative binding
interfaces required for normal RyR function.
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Figure 1.
Figure 1. Overall Structure of the RyR NTD
(A) Overall
fold of the RyR2 NTD, showing the α helix (α1) and 3[10] helix
(3[10]h1) in red, β strands in blue, and loops in white. Two
views are shown (labeled “front” and “back”), rotated
180° around a vertical axis. All β strands are labeled for
reference. Loops present in the construct but not modeled are
shown as dotted lines. W98 in the α1-β5 loop is shown in stick
representation. The positions of the amino- and carboxytermini
are indicated.
(B) Sequence alignment of the NTD of mouse
RyR2, rabbit RyR1, and human RyR3. Conserved residues are
highlighted in gray. Secondary structure elements are shown on
top (RyR2) and at the bottom (RyR1). Sequence stretches present
in the constructs but not modeled in the electron density are
shown as dotted lines. Positions found in disease mutations are
marked with an asterisk and highlighted in red.
(C)
Superposition of the backbone trace of RyR1 (green) and RyR2 NTD
(blue). Loops with conformational changes are highlighted. The
view is the same as the front view of Figure 1A.
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Figure 3.
Figure 3. RyR2 A77V and V186M Mutations Cause Distinct
Changes in the Surface
(A) Superposition of RyR2 wild-type
(blue) and RyR2 A77V (orange) in the region surrounding the
mutation. Nitrogen atoms are shown as dark blue, oxygen in red,
and sulfur in yellow. The inset shows the view (box) relative to
the full domain.
(B) Superposition of RyR2 wild-type (blue)
with RyR2 V186M (brown).
(C and D) Surface representation
of RyR2 wild-type (blue) with the surface of the superposed A77V
and V186M mutations shown as a mesh. The views are identical to
the ones for the corresponding Figures 3A and 3B. The A77V and
V186M mutations alter the local surface. Numbers shown are
solvent accessible areas, with the first number for the
wild-type residue, and the second for the mutant.
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The above figures are
reprinted
by permission from Cell Press:
Structure
(2009,
17,
1505-1514)
copyright 2009.
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