Occurrence of a kinetoplast DNA-protein complex in Trypanosoma cruzi

The kinetoplast DNA has been purified in high yield from $\text{Trypanosoma cruzi}$ by centrifugation on 3 M CsCl after lysis with a detergent. In exponentially growing trypanosomes, a light component causing a density shift of the kinetoplast DNA in CsCl density gradients is observed. This component is presumably a protein since it is removed by digestion with proteolytic enzymes. The DNA-protein complex is resistant to phenol extraction and 4 M guanidinium chloride, which indicates the possibility of a covalent bond between the protein and the DNA. The Kinetoplast DNA isolated from trypanosomes at the stationary phase by centrifugation on 3 M CsCl is free of proteins.