Biology Reference
In-Depth Information
A
B
UvrA
UvrB
t
1/2
=
28 s
i. Random diffusion
UvrA
ii. Directed motion
UvrA
iii. Intermittent motion
t
1/2
=
7 s
UvrA
2
: three dimensional
diffusion; static DNA binding
UvrA
2
B
2
: three modes of diffusion on
DNA
C
UvrB
UvrA
UvrA
UvrB
UvrB
F
IG
. 5. Summary of motion of UvrA
2
and UvrA
2
B
2
on DNA. (A) UvrA
2
has been shown to
perform a 3D search with an average bound life time of 7 s on DNA. UvrA
2
was also observed
jumping from DNA helix to another helix over distances of 1-2
m
m (not shown). (B) UvrB collapses
UvrA's search mode from 3D to 1D sliding and increases its average lifetime on DNA to 40 s. Three
different sliding modes were observed for UvrA
2
B
2
. (C) The nature of how UvrC finds its way to the
UvrB-DNA preincision complex is not known. The low concentrations of UvrC in the cell would
make a 3D search very inefficient if UvrC remained statically bound for longer than 1 s.
