 |
PDBsum entry 1a2b
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Oncogene protein
|
PDB id
|
|
|
|
1a2b
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Crystal structure of human rhoa in a dominantly active form complexed with a gtp analogue.
|
|
|
Authors
|
|
K.Ihara,
S.Muraguchi,
M.Kato,
T.Shimizu,
M.Shirakawa,
S.Kuroda,
K.Kaibuchi,
T.Hakoshima.
|
|
|
Ref.
|
|
J Biol Chem, 1998,
273,
9656-9666.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
The 2.4-A resolution crystal structure of a dominantly active form of the small
guanosine triphosphatase (GTPase) RhoA, RhoAV14, complexed with the
nonhydrolyzable GTP analogue, guanosine 5'-3-O-(thio)triphosphate (GTPgammaS),
reveals a fold similar to RhoA-GDP, which has been recently reported (Wei, Y.,
Zhang, Y., Derewenda, U., Liu, X., Minor, W., Nakamoto, R. K., Somlyo, A. V.,
Somlyo, A. P., and Derewenda, Z. S. (1997) Nat. Struct. Biol. 4, 699-703), but
shows large conformational differences localized in switch I and switch II.
These changes produce hydrophobic patches on the molecular surface of switch I,
which has been suggested to be involved in its effector binding. Compared with
H-Ras and other GTPases bound to GTP or GTP analogues, the significant
conformational differences are located in regions involving switches I and II
and part of the antiparallel beta-sheet between switches I and II. Key residues
that produce these conformational differences were identified. In addition to
these differences, RhoA contains four insertion or deletion sites with an extra
helical subdomain that seems to be characteristic of members of the Rho family,
including Rac1, but with several variations in details. These sites also display
large displacements from those of H-Ras. The ADP-ribosylation residue, Asn41, by
C3-like exoenzymes stacks on the indole ring of Trp58 with a hydrogen bond to
the main chain of Glu40. The recognition of the guanosine moiety of GTPgammaS by
the GTPase contains water-mediated hydrogen bonds, which seem to be common in
the Rho family. These structural differences provide an insight into specific
interaction sites with the effectors, as well as with modulators such as guanine
nucleotide exchange factor (GEF) and guanine nucleotide dissociation inhibitor
(GDI).
|
|
|
|
|
|
|
|
Figure 4.
Fig. 4. GTP  S bound to
RhoA^V14. A cartoon of GTP S binding
to RhoA^V14 with Mg2+ and water molecules. All dashed lines
correspond to hydrogen bonding interactions (distance less than
3.5 Å), and the corresponding distances (Å) are
indicated. The residues whose main chains participate in the
hydrogen bonding are represented by rectangles, and the residues
whose side chains participate in the hydrogen bonding are
represented by ovals. The coordination bonds to the Mg2+ ion are
indicated by arrows. The possible hydrogen bond between Gln63
and Wat-3 has a longer distance (3.8 Å). The hydrogen
bonds observed in the current structure but not in H-Ras are
highlighted in red.
|
|
Figure 6.
Fig. 6. Molecular surface of RhoA^V14. Residues whose
mutations abolish the interaction with GEF are in yellow. Asn41
is also highlighted in green. Switches I and II are shown in red
and blue, respectively. This surface also contains most of the
residues corresponding to the effector-binding residues as seen
in the complex between the Ras-binding domain of Raf1 and a
double mutant Rap1A (E30D/K31E), which mimics Ras.
|
|
|
|
|
|
The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(1998,
273,
9656-9666)
copyright 1998.
|
|
|
Secondary reference #1
|
|
|
Title
|
|
Refined crystal structure of the triphosphate conformation of h-Ras p21 at 1.35 a resolution: implications for the mechanism of gtp hydrolysis.
|
|
|
Authors
|
|
E.F.Pai,
U.Krengel,
G.A.Petsko,
R.S.Goody,
W.Kabsch,
A.Wittinghofer.
|
|
|
Ref.
|
|
Embo J, 1990,
9,
2351-2359.
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
|
|
|
|
