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Figure 3.
Figure 3: Architecture of the Na^+,K^+-ATPase alpha- beta- bold
gamma- complex
and the K^+/Rb^+ sites. The cytoplasmic side is up in all
panels. a, The  -,
 -
and  -subunits
are coloured blue, wheat and red, respectively. Helices are
represented by cylinders and -strands
by arrows. The -ectodomain
is shown by surface representation of the experimental electron
density. The transmembrane segments of the -subunit
are numbered (yellow) starting with the most N-terminal. The
small C-terminal helix (S, for switch) is light red. Mg^2+,
MgF[4]^2- and Rb^+ ions are grey, orange and pink, respectively.
b, The red mesh (anomalous difference Fourier map) and the green
mesh (omit F[O]-F[C] electron density map) show the positions of
Rb^+ and K^+ ions, respectively. Oxygen-containing side chains
within and close to the coordination sphere are shown. c,
Structural alignment of the Na^+,K^+-ATPase (blue) with SERCA
(yellow; PDB 1WPG) in the E2⋅MgF[4]^2- forms. Yellow and
magenta spheres represent water molecules in SERCA and K^+/Rb^+
ions in Na^+,K^+-ATPase, respectively. d, Interaction between
Glu 327 ( M4)
and Leu 97 ( M1)^17.
The cyan mesh indicates the electron-density map (2F[O]-F[C]) of
M1
contoured at 1.0  .
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