Figure 1.
Figure 1 a, The structure of the Cdc42Hs GMPPNP/p50rhoGAP
complex viewed along the protein-protein interface. Cdc42Hs is
coloured green, with the conserved switch I (residues 32 to 40),
switch II (residues 60 to 67) and P-loop (residues 10 to 17)
regions in red. These bind to a shallow depression in rhoGAP
(blue) formed by the A-Al loop and helices B and F which are
highlighted in magenta. Formation of the complex buries 1,807
ring
2of accessible surface, of which 61% (1,115 ring
2) is made up of non-polar side-chain atoms. The C positions
of Arg 85[r] and Tyr 64[c] are highlighted. b, Stereo view of
the interactions between Cdc42Hs and p50rhoGAP viewed from the
same direction as in a. Secondary-structure elements of Cdc42Hs
and rhoGAP are coloured green and blue respectively, with
Cdc42Hs side chains in grey and those of rhoGAP in yellow. In
both cases, oxygen and nitrogen atoms are red and blue
respectively. The electron density for residues 29-31 of the
switch I region of Cdc42Hs is poor. Electron density for Tyr
32[c] is relatively poor at the current state of refinement, but
it does refine adequately in a conformation which makes
additional contacts with Lys 189[r], Thr 191[r] and Asn 194[r],
Arg 85[r] occupies a conformation close to the P-loop of Cdc42Hs
and interacts either through direct hydrogen bonding with the
C=O of Gly 12[c] or through water mediated contacts. Gln61[c],
which is important in the GTP hydrolysis reaction, is disordered
in this structure as it is in X-ray structures of Ras. (Panels a
and b were produced using MOLSCRIPT29.)
The above figure is reprinted
by permission from Macmillan Publishers Ltd:
Nature
(1997,
388,
693-697)
copyright 1997.
GMPPNP/p50rhoGAP
complex viewed along the protein-protein interface. Cdc42Hs is
coloured green, with the conserved switch I (residues 32 to 40),
switch II (residues 60 to 67) and P-loop (residues 10 to 17)
regions in red. These bind to a shallow depression in rhoGAP
(blue) formed by the A-Al loop and helices B and F which are
highlighted in magenta. Formation of the complex buries 1,807
ring
2of accessible surface, of which 61% (1,115 
positions
of Arg 85[r] and Tyr 64[c] are highlighted. b, Stereo view of
the interactions between Cdc42Hs and p50rhoGAP viewed from the
same direction as in a. Secondary-structure elements of Cdc42Hs
and rhoGAP are coloured green and blue respectively, with
Cdc42Hs side chains in grey and those of rhoGAP in yellow. In
both cases, oxygen and nitrogen atoms are red and blue
respectively. The electron density for residues 29-31 of the
switch I region of Cdc42Hs is poor. Electron density for Tyr
32[c] is relatively poor at the current state of refinement, but
it does refine adequately in a conformation which makes
additional contacts with Lys 189[r], Thr 191[r] and Asn 194[r],
Arg 85[r] occupies a conformation close to the P-loop of Cdc42Hs
and interacts either through direct hydrogen bonding with the
C=O of Gly 12[c] or through water mediated contacts. Gln61[c],
which is important in the GTP hydrolysis reaction, is disordered
in this structure as it is in X-ray structures of Ras. (Panels a
and b were produced using MOLSCRIPT29.)