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Figure 2.
Fig. 2. Stereo views of an electron density map of the yeast
F[1]c[10] complex. The solvent flattened map was calculated at
3.9 Å resolution and contoured at 1.5  . (A) Side
view containing the bovine F[1] C  model
(with in
orange,  in yellow,
and  in
green). The density of symmetry-related molecules in the crystal
is masked out. The inset indicates the location of the subunits
within the complex. The location of the section shown in (C) is
indicated by the white box; the direction of the view is
indicated by the arrow. The presumed membrane region (M) (2) is
marked by the two dotted lines. The c subunits are numbered 3,
2, 1, 10, and 9 (the best ordered c subunit was chosen as
number 1). The overall height of the complex is ~190 Å, of
which the [3] [3]
subcomplex accounts for 83 Å, the stalk for 50 Å,
and the c subunits for 58 Å. (B) Enlarged view of the  / -c contact
region with the model (and numbering) of the E. coli  subunit
(in red) and the E. coli c subunit (in white) fitted into the
density, contoured at 1.0 . The
white box in the inset indicates the location of the displayed
section within the complex. (C) End-on view of the density of
the c ring. The inset shows the location of the , , , and subunits
in relation to the c subunits. The helices of the c subunit are
drawn as blue circles, the larger outer circles accounting for
the larger side chains in the COOH-terminal helix. The outer
diameter of the c ring is 55 Å (top) to 42 Å
(equator) to 45 Å (bottom), and the inner diameter is 27
Å (top) to 17 Å (equator) to 22 Å (bottom).
The dimensions exclude consideration of unresolved regions of
density, including amino acid side chains and detergent or lipid
molecules. The two regions of density near subunit 10 are not
extensive and are likely to be noise.
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