Characterization of hMre11
DNA-binding properties. (A) Radiolabeled 50 nt
ssDNA (MJ19; left) or dsDNA (MJ19/MJ20; right) was incubated
at 1.25 nM with hMre11 at 50 nM. After 15 min incubation, the indicated
nucleotide excess non-radioactively-labeled competitor DNA was added
and incubation was continued for an additional 15 min. Competitor
DNA was single-stranded oligonucleotide (MJ19) or circular φX174
ssDNA (left) and blunt-ended double-stranded oligonucleotide (MJ19/MJ20)
or circular φX174 dsDNA (right). Lane ‘–’,
incubation without hMre11. Samples were analyzed by native PAGE,
followed by autoradiography. (B) Radiolabeled 50
nt ssDNA (MJ19) was incubated at 1.25 nM with 50 nM hMre11 as in
(A). Non-labeled, non-identical ssDNA (DG73) or dsDNA (DG73/DG74)
oligonucleotide DNA was used as a competitor. Values on the y-axis
are reciprocal fractions of DNA–protein complex, normalized
to the fraction of DNA–protein complex in non-competed
reactions (Materials and Methods). Bars indicate standard deviations
of mean values of triplicate reactions. Slopes of linear regression
lines through the datapoints are indicated.