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PDBsum entry 2of3
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Structural protein, cell cycle
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PDB id
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2of3
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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 structure of a tog domain: conserved features of xmap215/dis1-Family tog domains and implications for tubulin binding.
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Authors
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J.Al-Bassam,
N.A.Larsen,
A.A.Hyman,
S.C.Harrison.
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Ref.
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Structure, 2007,
15,
355-362.
[DOI no: ]
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PubMed id
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Abstract
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Members of the XMAP215/Dis1 family of microtubule-associated proteins (MAPs) are
essential for microtubule growth. MAPs in this family contain several 250
residue repeats, called TOG domains, which are thought to bind tubulin dimers
and promote microtubule polymerization. We have determined the crystal structure
of a single TOG domain from the Caenorhabditis elegans homolog, Zyg9, to 1.9 A
resolution, and from it we describe a structural blueprint for TOG domains.
These domains are flat, paddle-like structures, composed of six HEAT-repeat
elements stacked side by side. The two wide faces of the paddle contain the
HEAT-repeat helices, and the two narrow faces, the intra- and inter-HEAT repeat
turns. Solvent-exposed residues in the intrarepeat turns are conserved, both
within a particular protein and across the XMAP215/Dis1 family. Mutation of some
of these residues in the TOG1 domain from the budding yeast homolog, Stu2p,
shows that this face indeed participates in the tubulin contact.
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Figure 2.
Figure 2. Structure of Zyg9-TOG3
(A) Zyg9 TOG3 has seven
HEAT repeats. HR0 contains helices 0A and 0B (red) linked by a
14 residue loop (T0). The six HEAT repeats that follow (blue
helices, HR1–HR6) form the conserved TOG domain structure. In
this view, the A helices (1A–6A) are in the front, the B
helices (1B–6B), in the rear; turns between A and B helices of
each repeat (T1–T6) are at the bottom, and interrepeat turns
(T2-3 and T3-4) are at the top. The HR5 A helix is broken by a
nonhelical linker into helices 5A1 and 5A2. HR6 packs onto HR5
with a right-handed 45° twist. There is a short β-ribbon
(yellow strands, S0 and S1) at the N terminus.
(B) As in
(A), but viewed from the bottom (structure rotated by 90°).
(C) As in (A), but structure rotated by 180°.
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Figure 4.
Figure 4. Surface Representation of Zyg9-TOG3 Showing
Conservation of Solvent-Exposed Residues on One Narrow Face of
the Paddle-like Structure
Conserved, solvent-exposed
residues are shown in the color scheme of Figure 3. (A) View as
in Figure 1B. (B) View as in Figure 1C, showing the relative
dimensions of the domain and of the conserved surface.
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The above figures are
reprinted
by permission from Cell Press:
Structure
(2007,
15,
355-362)
copyright 2007.
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