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PDBsum entry 1iap
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Signaling protein
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PDB id
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1iap
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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 rgrgs domain of p115rhogef.
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Authors
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Z.Chen,
C.D.Wells,
P.C.Sternweis,
S.R.Sprang.
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Ref.
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Nat Struct Biol, 2001,
8,
805-809.
[DOI no: ]
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PubMed id
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Abstract
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p115RhoGEF, a guanine nucleotide exchange factor for Rho GTPase, is also a
GTPase activating protein (GAP) for G(12) and G(13) heterotrimeric G alpha
subunits. Near its N-terminus, p115RhoGEF contains a domain (rgRGS) with remote
sequence identity to RGS (regulators of G protein signaling) domains. The rgRGS
domain is necessary but not sufficient for the GAP activity of p115RhoGEF. The
1.9 A resolution crystal structure of the rgRGS domain shows structural
similarity to RGS domains but possesses a C-terminal extension that folds into a
layer of helices that pack against the hydrophobic core of the domain.
Mutagenesis experiments show that rgRGS may form interactions with G alpha(13)
that are analogous to those in complexes of RGS proteins with their G alpha
substrates.
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Figure 1.
Figure 1. Structure of the rgRGS domain of p115RhoGEF. a,
Stereo view of the C  trace
of the rgRGS domain. b, Representative 2F[o] - F[c] electron
density, contoured at 1.5  ,
in the neighborhood surrounding the C-terminus of the 4
helix of p115RhoGEF. c, Ribbon diagram depicting the tertiary
structure of rgRGS domain. The rgRGS domain consists of 11
helices with boundaries defined in Fig. 2b and color-coded in
correspondence to their counterparts in RGS4 (ref. 11). The
C-terminal four helices not present in RGS domains are colored
red. Figures were prepared using Gl_render32, BOBSCRIPT33 and
POV-ray34.
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Figure 3.
Figure 3. A model of the rgRGS -G  [13]
complex. a, rgRGS domain is colored according to the scheme
in Fig. 1, and G [13]
is colored gray. Switch regions of G [13]
are shown in plum. Residues 124 -129 in G [13]
could not be modeled reliably and so were omitted from the
model. b, Putative contacts between p115RhoGEF rgRGS domain and
G [13]
L3 - 3
and L5 segments of rgRGS are colored yellow and green,
respectively; switch I and switch II of G [13]
are colored plum. Side chains proposed to form specific contacts
are depicted as ball-and-stick models. Oxygen, nitrogen and
carbon atoms are colored red, blue and black, respectively.
Putative hydrogen bonds are indicated by dotted lines. c,
Structure of RGS4 -G [i1]
complex11 is shown in the same orientation and color scheme.
GDP, AlF[4]^- and the catalytic water molecule as bound in the
active site of G [i1]
are shown as ball-and-stick models.
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
Nat Struct Biol
(2001,
8,
805-809)
copyright 2001.
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