Figure 1.

Purification of mIHF from M. smegmatis. (a) SDS/PAGE of protein fractions eluted from an Econo-Pac S column. Aliquots of the sample loaded onto an Econo-Pac S column (post-Hep), and fractions 67–76 (as indicated) eluted from the column with a salt gradient are shown. (b) Econo-Pac S fractions 69–73 stimulate recombination. Aliquots of the fractions shown in a were added to recombination reactions containing supercoiled attP plasmid DNA (pMH39; 3.7 kb), a 0.6-kb linear radiolabeled attB DNA and L5 integrase; the products were separated by agarose gel electrophoresis and visualized by autoradiography. The Econo-Pac S fractions used for each reaction and a control reaction without mIHF (−) are indicated. Fractions 69–73 stimulate L5 Int-mediated recombination between attP and attB to produce a 4.3-kb linear product.