Nucleic acid binding by nsp10. Binding mixtures containing (A) 80 pmol double-stranded RNA, (B) 82 pmol double-stranded DNA, (C) 100 pmol single-stranded RNA, or (D) no nucleic acid were incubated with various concentrations of nsp10. Binding mixtures shown in lanes 0 to 7 contained 0, 10, 20, 40, 80, 160, 320, and 800 μM nsp10, respectively. Free and bound nucleic acids were detected by SYBR-gold staining (Invitrogen). A double-stranded DNA ladder (1 Kb Plus; Invitrogen) was included as a marker (lane M). The positions of free nucleic acid (F), shifted nucleic acid-nsp10 complexes (S), and supershifted multiplexes (O) on the gels are indicated at the left. The shifted and supershifted nucleic acid peaks coincide with SYPRO-ruby protein stain in each gel (not shown).