Le Cam E, Frechon D, Barray M, Fourcade A, Delain E
Laboratoire de Microscopie Cellulaire et Moléculaire, Centre National de la Recherche Scientifique, Villejuif, France.
Proc Natl Acad Sci U S A. 1994 Dec 6;91(25):11816-20. doi: 10.1073/pnas.91.25.11816.
The Fur (ferric uptake regulation) protein is a global regulator that, in the presence of Fe2+, represses the expression of a number of iron-acquisition genes and virulence determinants such as toxins. Dark-field electron microscopy of positively stained Fur-DNA complexes in addition to atomic force microscopy allowed direct visualization of Fur interactions with the regulatory regions of aerobactin and hemolysin operons and provided complementary information about the structure of the complexes. According to the DNA used and the protein/DNA ratio, Fur binding to DNA results in partial or total covering of the fragments, indicating that the protein initiates polymerization along the DNA molecules at specific sites. Negative staining of Fur-DNA complexes revealed a well-ordered structure of the polymer suggesting a helical arrangement. Local rigidification of the DNA molecules resulting from Fur binding could be involved in the repression process.
铁摄取调节（Fur）蛋白是一种全局调节因子，在Fe2+存在的情况下，它会抑制许多铁获取基因和毒力决定因素（如毒素）的表达。除了原子力显微镜外，对阳性染色的Fur-DNA复合物进行暗场电子显微镜观察，可以直接观察到Fur与气杆菌素和溶血素操纵子调控区域的相互作用，并提供有关复合物结构的补充信息。根据所用的DNA和蛋白质/DNA比例，Fur与DNA的结合会导致片段的部分或完全覆盖，这表明该蛋白质在特定位点沿着DNA分子起始聚合。Fur-DNA复合物的负染色显示聚合物具有有序的结构，表明呈螺旋排列。Fur结合导致的DNA分子局部刚性化可能参与了抑制过程。
