Figure 4. SDS-PAGE analysis of crosslinked IntI1•DNA complexes.

IN (2 pmoles) was preincubated with the 5′-end radiolabeled dsattI1 (A), dsattC (B), ssattI1 (C, bs and ts), ssattC (D, bs and ts) for 30 min in the presence of AHDAP at 37°C (final volume 20 µl). Products were separated by electrophoresis on 12% SDS-PAGE gel. The gel was then dried and autoradiographed. The positions of monomers, dimers and tetramers bound to DNA were determined by comparison with the migration distance of protein weight markers (BIO-RAD) submitted to electrophoresis under the same conditions. F: free substrate.