ESCHERICHIA-COLI MUKB PROTEIN INVOLVED IN CHROMOSOME PARTITION FORMS A HOMODIMER WITH A ROD-AND-HINGE STRUCTURE HAVING DNA-BINDING AND ATP/GTP BINDING ACTIVITIES
ESCHERICHIA-COLI MUKB PROTEIN INVOLVED IN CHROMOSOME PARTITION FORMS A HOMODIMER WITH A ROD-AND-HINGE STRUCTURE HAVING DNA-BINDING AND ATP/GTP BINDING ACTIVITIES
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DOI：
10.1002/j.1460-2075.1992.tb05617.x
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发表时间：
1992-12-01
期刊：
影响因子：
11.4
通讯作者：
HIRAGA, S
中科院分区：
文献类型：
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作者：
NIKI, H;IMAMURA, R;HIRAGA, S
大肠杆菌的 mukB 突变体在复制染色体的正确分配方面存在缺陷。这导致细胞增殖过程中出现正常大小的无核（无染色体）细胞。根据mukB基因的核苷酸序列，预测177 kDa的MukB蛋白是一种末端具有球状结构域的丝状蛋白，并且还具有DNA结合和核苷酸结合能力。在这里，我们提供的证据表明纯化的 MukB 蛋白具有这些特征。 MukB 形成具有杆铰链结构的同二聚体，一端有一对大的 C 端球状结构域，另一端有一对小的 N 端球状结构域；它倾向于在杆部分的中间铰接处弯曲。 DNA-纤维素柱色谱和凝胶阻滞测定表明 MukB 具有 DNA 结合活性。光亲和交联实验表明，在 Zn2+ 存在的情况下，MukB 与 ATP 和 GTP 结合。在整个纯化步骤中，酰基载体蛋白与 MukB 共纯化。
mukB mutants of Escherichia coli are defective in the correct partitioning of replicated chromosomes. This results in the appearance of normal-sized anucleate (chromosome-less) cells during cell proliferation. Based on the nucleotide sequence of the mukB gene, the MukB protein of 177 kDa was predicted to be a filamentous protein with globular domains at the ends, and also having DNA binding and nucleotide binding abilities. Here we present evidence that the purified MukB protein possesses these characteristics. MukB forms a homodimer with a rod-and-hinge structure having a pair of large, C-terminal globular domains at one end and a pair of small, N-terminal globular domains at the opposite end; it tends to bend at a middle hinge site of the rod section. Chromatography in a DNA-cellulose column and the gel retardation assay revealed that MukB possesses DNA binding activity. Photoaffinity cross-linking experiments showed that MukB binds to ATP and GTP in the presence of Zn2+. Throughout the purification steps, acyl carrier protein was co-purified with MukB.