Figure 9.

Complexes are stable to freezing and thawing. Purified complexes (3 nM) made with Alexa Fluor-680 streptavidin were treated by freezing 20 μl aliquots in liquid nitrogen, storing overnight at −80 and thawing at 20°C. Treated samples (FT) were in buffer C alone (buf) or in buffer C plus 25% glycerol (gly). The thawed complexes were tested for activity by incubating 2 μl of complexes in the presence or absence (±) of 200 μM each of dATP, dCTP, dGTP and dTTP in a final volume of 10 μl buffer C at 55°C for 30 min. Primer extension products were resolved by electrophoresis in a 1.5% agarose gel and the labeled streptavidin component was imaged using a LI-COR Odyssey infrared imager. An unfrozen control was held overnight at 4°C (untreated).