hMre11 binds to ssDNA and
dsDNA molecules. (A) Radiolabeled 50 nt ssDNA or
blunt-ended dsDNA (MJ19 and MJ19/20, respectively) were
incubated at 1.25 nM with the indicated amounts of hMre11 under
standard conditions in the absence of divalent cations. Samples
were analyzed by native PAGE, followed by autoradiography. nb, non-bound
probe; b, bound probe; DNA–protein complex. (B)
Biotinylated 50 nt ssDNA or blunt-ended dsDNA (MJ29 and MJ29/20,
respectively) were coupled to streptavidin-coated magnetic beads
and incubated at 20 nM with 24 nM hMre11 preparation under standard
conditions supplemented with 0.1% NP-40. Bound fractions
were analyzed by SDS–PAGE and immunoblotting with affinity-purified α-hMre11 antibodies. Lane 1, size marker
(m, molecular mass indicated in kDa); lane 2, incubation with control
beads lacking DNA; lane 3, incubation with beads coupled to ssDNA;
lane 4, incubation with beads coupled to dsDNA.