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Figure 7.
FIGURE 7. Comparison of primer ddC orientations in the
O^6-BzG:ddC-1 and O^6-BzG:ddC-2 structures and a view of the
O^6-BzG:G active site. A, stereo view of the superimposed
(r.m.s. deviation = 0.344) O^6-BzG:ddC-1 (Dpo4 (light blue) and
nucleotides and ions (dark blue)) and O^6-BzG:ddC-2 (Dpo4, ions,
and nucleotides (orange)) structures. Dpo4 is shown in schematic
diagram form for both structures. The incoming dGTP (magenta)
from the O^6-BzG:ddC-1 structure is shown in ball and stick
form. The 14th nucleotide (dark blue, ddC) from the
O^6-BzG:ddC-1 structure forms a wobble pair with O^6-BzG, but
the 14th nucleotide (orange, ddC) from the O^6-BzG:ddC-2 ternary
complex is moved into a noninstructional conformation. B, stereo
view of the O^6-BzG:G active site. Dpo4 (light blue) is shown in
schematic diagram form. The last two primer residues, p14C and
p15G, and the O^6-BzG lesion are shown in ball and stick form
(dark blue). The 14th base in the primer, p14C, is placed in a
conformation similar to that observed in the O^6-BzG:ddC-2
structure. The calcium ions (light brown) and incoming dGTP
(magenta) are also shown.
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