Isolation of maxicircle component of kinetoplast DNA from hemoflagellate protozoa.

Maxicircle DNA has been isolated from the kinetoplast DNA of Leishmania tarentolae culture forms by bouyant separation in CsCl in the presence of the A + T-binding dye Hoechst 33258, after liberation from the kinetoplast DNA network by cleavage with the single-hit restriction endonuclease EcoRI. The purified linearized maxicircle DNA has a density in CsCl of 1.681 g/cm3 (79% A + T) and a molecular weight of approximately 18-20 x 10(6). The maxicircle molecule exhibited intramolecular base composition heterogeneity ranging from 85% A + T to 74% A + T.