Scafati A R, Araco A, Belli M, Falbo V, Giorgi C, Maggini M
Nucleic Acids Res. 1976 Sep;3(9):2171-82. doi: 10.1093/nar/3.9.2171.
An investigation has been made on structure modifications of E. coli ribosomes following EDTA treatment. When completely deprived of magnesium, the small subunit sediments at 16S while the large one, in the same conditions, shows two components at 17S and 21S. Unfolding causes in both subunits an increase in radius of gyration without substantial change in molecular weight, as shown by light scattering measurements. The occurence of the slower 17S component besides the 21S one has to be connected with a fraction of the large subunit population which presents nucleolytic breaks in its RNA chain. These breaks do not cause fragmentation of the unfolded subunit but lead to a more open configuration sedimenting at lower velocity.
对经乙二胺四乙酸(EDTA)处理后的大肠杆菌核糖体结构变化进行了研究。当完全去除镁离子时,小亚基在16S处沉降,而在相同条件下,大亚基显示出在17S和21S处的两个组分。如光散射测量所示,展开导致两个亚基的回转半径增加,而分子量没有实质性变化。除了21S组分外,较慢的17S组分的出现与大亚基群体的一部分有关,该部分在其RNA链中存在核酸酶切割。这些切割不会导致展开的亚基碎片化,但会导致形成更开放的构象,以较低速度沉降。