Figure 3 The C-terminal domain of reverse gyrase and its
interaction with the N-terminal domain. (A) Superposition of the
C-terminal domain with the 67-kDa catalytic fragment of E.coli
topoisomerase I (Lima et al., 1994), shown in grey. The position
of domains II and III of topoisomerase I correspond to the
'closed' form of the enzyme. A box encloses the region featured
in (B). (B) Stereo view of reverse gyrase superimposed with
domains II and III of topoisomerase I in the putative 'open'
form (Feinberg et al., 1999). The catalytic Tyr in both enzymes
is indicated in red space-filling representation. The arrow
indicates the putative movement of reverse gyrase subdomains T2
and T3 during strand passage. This movement would be prevented
by subdomain H3 in its current position.
The above figure is reprinted
from an Open Access publication published by Macmillan Publishers Ltd: