Fig. 1. Schematic structure of Dicer and SDS–PAGE analysis of recombinant Dicer preparations. (A) Domains of human Dicer. Amino acid positions corresponding to domain borders, and a P-loop sequence with the K70A mutation are indicated. (B) Dicer-HisN (1 µg), Dicer-HisC (0.5 µg) and Dicer-HisC P-loop mutant K70A (1 µg) were analysed by 8% SDS–PAGE. Proteins were stained with GelCode Blue Stain Reagent (Pierce). Lanes M, protein size markers in kDa (BenchMark Protein Ladder, Invitrogen).