Figure 1.

Purified four-subunit Y831A Pol ε. SDS-PAGE analysis of peak fraction from final SMART MonoS column (see Methods). 1 μl of collected fraction 15 was mixed with Invitrogen loading buffer and run on denaturing 4–12% NUPAGE Bis-Tris polyacrylamide gel for 50 minutes at 200 V in MOPS buffer. The gel was stained with SimpleStain colloidal blue stain as recommended by the vendor (Invitrogen). Lane 1, Pol ε Y831A; lane 2, the Benchmark His-tagged protein standards (Invitrogen).