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PDBsum entry 2v8c
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Protein binding
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PDB id
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2v8c
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References listed in PDB file
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Key reference
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Title
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High-Resolution structural analysis of mammalian profilin 2a complex formation with two physiological ligands: the formin homology 1 domain of mdia1 and the proline-Rich domain of vasp.
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Authors
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P.Kursula,
I.Kursula,
M.Massimi,
Y.H.Song,
J.Downer,
W.A.Stanley,
W.Witke,
M.Wilmanns.
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Ref.
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J Mol Biol, 2008,
375,
270-290.
[DOI no: ]
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PubMed id
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Abstract
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Profilins are small proteins capable of binding actin, poly-l-proline and other
proline-rich sequences, and phosphatidylinositol (4,5)-bisphosphate. A number of
proline-rich ligands for profilin have been characterised, including proteins of
the Ena/VASP and formin families. We have determined the high-resolution crystal
structures of mouse profilin 2a in complex with peptides from two functionally
important ligands from different families, VASP and mDia1. The structures show
that the binding mode of the peptide ligand is strongly affected by the
non-proline residues in the sequence, and the peptides from VASP and mDia1 bind
to profilin 2a in distinct modes. The high resolution of the crystallographic
data allowed us to detect conserved CH-pi hydrogen bonds between the peptide and
profilin in both complexes. Furthermore, both peptides, which are shown to have
micromolar affinity, induced the dimerisation of profilin, potentially leading
to functionally different ligand-profilin-actin complexes. The peptides did not
significantly affect actin polymerisation kinetics in the presence or in the
absence of profilin 2a. Mutant profilins were tested for binding to
poly-L-proline and the VASP and mDia1 peptides, and the F139A mutant bound
proline-rich ligands with near-native affinity. Peptide blotting using a series
of designed peptides with profilins 1 and 2a indicates differences between the
two profilins towards proline-rich peptides from mDia1 and VASP. Our data
provide structural insights into the mechanisms of mDia1 and VASP regulated
actin polymerisation.
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Figure 1.
Figure 1. The profilin ligands used in the current study. (a)
A diagram of the structures of the profilin 2a ligands, mDia1
and VASP. For mDia1, the domains are as follows: GBD,
Rho-GTPase-binding domain; DID, diaphanous inhibitory domain;
DD, dimerisation domain; CC, coiled-coil domain; FH1, formin
homology domain 1; FH2, formin homology domain 2; DAD,
diaphanous autoinhibitory domain. The regions N-terminal to the
FH1 domain have been referred to in the literature as the FH3
domain. For VASP, the EVH1 domain, the proline-rich domain, and
the EVH2 domain are indicated. The EVH2 domain contains a WH2
domain (dark grey), an F-actin binding domain (light grey), and
a tetramerisation domain (white). The sequences of the peptides
used in this study are shown below the profilin-binding domains.
(b) The sequence of the FH1 domain of mDia1, which has 13 highly
homologous proline-rich repeats arranged in tandem. The peptide
used in this study, containing two binding motifs, is underlined.
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Figure 3.
Figure 3. Binding site determinants. (a) Stereo view of the
binding site for the VASP peptide, showing hydrogen bond
interactions and several residues discussed in the text. (b)
Superposition of the peptide binding modes from the VASP
(proline, orange; glycine, red) and mDia1 (proline, green;
non-proline, blue) complexes. The N termini of the peptides
point right in the Figure.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2008,
375,
270-290)
copyright 2008.
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