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PDBsum entry 3gq2
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Transport protein
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PDB id
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3gq2
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References listed in PDB file
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Key reference
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Title
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Structural and functional analysis of the globular head domain of p115 provides insight into membrane tethering.
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Authors
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Y.An,
C.Y.Chen,
B.Moyer,
P.Rotkiewicz,
M.A.Elsliger,
A.Godzik,
I.A.Wilson,
W.E.Balch.
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Ref.
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J Mol Biol, 2009,
391,
26-41.
[DOI no: ]
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PubMed id
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Abstract
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Molecular tethers play a central role in the organization of the complex
membrane architecture of eukaryotic cells. p115 is a ubiquitous, essential
tether involved in vesicle transport and the structural organization of the
exocytic pathway. We describe two crystal structures of the N-terminal domain of
p115 at 2.0 A resolution. The p115 structures show a novel alpha-solenoid
architecture constructed of 12 armadillo-like, tether-repeat (TR), alpha-helical
tripod motifs. We find that the H1 TR binds the Rab1 GTPase involved in ER to
Golgi transport. Mutation of the H1 motif results in the dominant negative
inhibition of ER to Golgi trafficking. We propose that the H1 helical tripod
contributes to the assembly of Rab-dependent complexes responsible for the
tether and SNARE-dependent fusion of membranes.
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Figure 2.
Fig. 2. Salt bridges and hydrogen bond interactions involved
in p115^Nt dimerization. Hydrogen bonds and salt bridges are
shown as broken lines, with interacting residues in
ball-and-stick representation.
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Figure 3.
Fig. 3. Tether repeat (TR) motif. (a) Structural features of
the 12 TRs in the p115^Nt monomer. Except for the C-terminal TR,
each TR includes three α-helices, which are shown in salmon,
yellow and light blue, respectively. The insertions between any
adjacent helices are colored gray. Arg39 is shown in
ball-and-stick representation; the side view is in the left-hand
panel, and the top view is in the right-hand panel. (b) The
conformation of three adjacent tether repeats (TR5, TR6, and
TR7) highlights the tight packing of the conserved hydrophobic
core throughout the solenoid, where the hydrophobic residues
involved in stabilizing the solenoid are shown in ball-and-stick
representation. (c) Superimposition of the three 12 TR motifs
from the dimer and monomer p115^Nt structures show the
structural conservation.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2009,
391,
26-41)
copyright 2009.
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