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Figure 2.
Figure 2. The gate helices in the L2-free and L2-bound
subunits. (a) and (b) The L2-free open (a) and L2-bound (b)
configurations of the SC (marked by yellow hydrophobic residues)
correspond to the uniform (magenta (a)) and distorted (orange
(b)) conformations of the gate helix. The remainder of the
subunits is shown in gray. The PDHK active site is marked by the
modeled (PDB ID 1Y8P) ATP molecule. (c) and (d) Superposition of
the L2-free (magenta (c)) and L2-bound (orange (d)) PDHK gate
helices with the RNA polymerase bridge helix (white) observed in
the uniform (c) and locally distorted (d) conformations. (e)
Stereo view of the L2-bound subunit showing stabilization of the
partially unwound gate helix. The hydrogen bonds are shown by
magenta broken lines. The active site is marked by ATP as in (a)
and (b). The views in (a), (b), and (e) are the same as in
Figure 1(b).
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