Figure 4

Comparison of combined SIN/DMSO effect on TaqII REase cleavage patterns of custom PCR substrates with and without a cognate recognition sequence. (A) and (B) Digestion of PCR substrate with a single 5′-GACCGA-3′ sequence. 0.3 μg (1.2-pmol GACCGA recognition sites) PCR(SINGLE) substrate was digested with 6 pmol TaqII at pH 8.0 in the presence of 10 mM (NH₄)₂SO₄, (panel A) or at pH 6.0, no salt added (panel B), for 16 h at 65°C. (A) Lane M, Sigma PCR 20-bp Low Ladder (selected bands marked); lane K, undigested PCR fragment; lanes 1–6, PCR fragment digested with TaqII: lane 1, without SIN and DMSO; lane 2, with SIN, no DMSO; lane 3, 20% DMSO only; lane 4, with SIN and 20% DMSO; lane 5, 30% DMSO only; lane 6, with SIN and 30% DMSO. (C) and (D) Digestion of PCR substrate devoid of the TaqII recognition sequence. All the reactions were performed as in Panels A and B, except that the PCR(SINGLE) substrate was replaced by PCR(WT) substrate, containing no cognate TaqII recognition site.