Fig. (2) Purification of the Halobacterium MCM helicase. Uninduced and induced E. coli cells harboring pET-MCM (lanes 2 and 3) and pET-MCMint (lanes 5 and 6) and the purified MCM protein (0.5 µg) with intein (lane 4) and without intein (lane 7) were fractionated on 10% SDS-PAGE. Lane 1, molecular weight markers.