Figure 2.

DNA and protein content of archaeal nucleosomes. (a) Electrophoretic separation of DNA fragments protected from MN digestion in nucleoprotein complexes isolated from formaldehyde-fixed M. fervidus. MN digestion was for 1, 2, 4, 6, 8, 10, 15, 30, and 45 min at 37°C. Control tracks contained size standards and undigested complexes (O). (b) Electrophoretic separation and silver staining of the proteins isolated from the complexes indicated in a that protected ≈60 bp fragments of DNA from MN digestion. Purification of these proteins involved incubations with β-agarase and DNase I, and the control tracks demonstrate the polypeptides present in these reagents. Small amounts of these polypeptides remained in the experimental material. An immunoblot of the purified proteins generated with anti-HMf antibodies is shown adjacent to the stained gel.