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PDBsum entry 1f7c
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Signaling protein
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PDB id
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1f7c
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Structure of the bh domain from graf and its implications for rho gtpase recognition.
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Authors
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K.L.Longenecker,
B.Zhang,
U.Derewenda,
P.J.Sheffield,
Z.Dauter,
J.T.Parsons,
Y.Zheng,
Z.S.Derewenda.
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Ref.
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J Biol Chem, 2000,
275,
38605-38610.
[DOI no: ]
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PubMed id
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Abstract
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Cellular signaling by small G-proteins is down-regulated by GTPase-activating
proteins (GAPs), which increase the rate of GTP hydrolysis. The GTPase regulator
associated with focal adhesion kinase (Graf) exhibits GAP activity toward the
RhoA and Cdc42 GTPases, but is only weakly active toward the closely related
Rac1. We determined the crystal structure of a 231-residue fragment of Graf
(GrafGAP), a domain containing the GAP activity, at 2.4-A resolution. The
structure clarifies the boundaries of the functional domain and yields insight
to the mechanism of substrate recognition. Modeling its interaction with
substrate suggested that a favorable interaction with Glu-95 of Cdc42 (Glu-97 of
RhoA) would be absent with the corresponding Ala-95 of Rac1. Indeed, GrafGAP
activity is diminished approximately 40-fold toward a Cdc42 E95A mutant, whereas
a approximately 10-fold increase is observed for a Rac1 A95E mutant. The GrafGAP
epitope that apparently interacts with Glu-95(Glu-97) contains Asn-225, which
was recently found mutated in some myeloid leukemia patients. We conclude that
position 95 of the GTPase is an important determinant for GrafGAP specificity in
cellular function and tumor suppression.
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Figure 1.
Fig. 1. Structure of GrafGAP. A, this stereo view of the
final 2F[o]  F[c] map,
contoured at 1.0  , shows the
electron density of Leu-193, which stabilizes the N-terminal
boundary of the BH domain. B, the ribbon drawing colored from
the N terminus (blue) to C terminus (red) illustrates the
overall fold of GrafGAP. Secondary elements are labeled as for
structures of BH[PI3-K] and p50RhoGAP (7, 26). This figure was
prepared with BOBSCRIPT (27).
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Figure 4.
Fig. 4. Amino acid type at position 95 of Cdc42 or Rac1
is an important determinant for GrafGAP activity. The relative
sensitivity of 5 µM Rho GTPases to activation were
measured in the absence ( open bars) or presence of 50 nM
GrafGAP (dashed bars) or 200 nM GrafGAP (double-dashed bars) by
the nitrocellulose filter binding assay.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2000,
275,
38605-38610)
copyright 2000.
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Secondary reference #1
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Title
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Expression, Purification and crystallization of a bh domain from the gtpase regulatory protein associated with focal adhesion kinase.
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Authors
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P.J.Sheffield,
U.Derewenda,
J.Taylor,
T.J.Parsons,
Z.S.Derewenda.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 1999,
55,
356-359.
[DOI no: ]
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PubMed id
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Figure 1.
Figure 1 Protein-sequence alignment of BH[GRAF], p85  subunit
and RhoGAP showing position of the helices in boxes. Full length
BH[GRAF] sequence corresponds to BH[GRAF(i)]. The stop codon was
introduced after the Leu triplet at position 231. BH[GRAF(ii)]
extends from Met12 to Leu231 and BH[GRAF(iii)] from Ser1 to
Leu231.
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The above figure is
reproduced from the cited reference
with permission from the IUCr
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