Bakke A C, Wu J R, Bonner J
Proc Natl Acad Sci U S A. 1978 Feb;75(2):705-9. doi: 10.1073/pnas.75.2.705.
The structure of Dictyostelium discoideum chromatin has been studied by the following techniques: electron microscopy, staphylococcal nuclease digestion, acrylamide gel electrophoresis, sucrose gradient centrifugation, and melting. The basic unit of chromatin is the nucleosome, which is a particle 98.6 A in diameter. Approximately 50% of the chromatin is protected from nuclease digestion, but this decreases when protease activity is not inhibited. The nucleosome contains 187 base pairs of DNA, including a 137-base-pair core and a 50-base-pair linker. The monomer nucleosome has an s20,w value of 11.5 S on isokinetic sucrose gradients. When the chromatin is melted, four transitions are observed, at 54.5 degrees, 66.7 degress, 74.9 degrees, and 79.7 degrees. The structure of Dictyostelium chromatin is very similar to that seen in higher eukaryotes.
电子显微镜、葡萄球菌核酸酶消化、丙烯酰胺凝胶电泳、蔗糖梯度离心和热变性。染色质的基本单位是核小体，其为直径98.6埃的颗粒。约50%的染色质可免受核酸酶消化，但在蛋白酶活性未受抑制时，这一比例会降低。核小体包含187个碱基对的DNA，包括一个137碱基对的核心和一个50碱基对的连接区。在等动力学蔗糖梯度上，单体核小体的s20,w值为11.5 S。当染色质发生热变性时，可观察到四个转变温度，分别为54.5℃、66.7℃、74.9℃和79.7℃。盘基网柄菌染色质的结构与高等真核生物中所见的结构非常相似。
