DNA-STIMULATED ATPASE ACTIVITY ON THE LON (CAPR) PROTEIN
DNA-STIMULATED ATPASE ACTIVITY ON THE LON (CAPR) PROTEIN
复制标题
DOI：
10.1128/jb.158.1.195-201.1984
复制
发表时间：
1984-01-01
影响因子：
3.2
通讯作者：
MARKOVITZ, A
中科院分区：
文献类型：
--
作者：
CHARETTE, MF;HENDERSON, GW;MARKOVITZ, A
大肠杆菌中多效性 lon（也称为 capR）基因座的基因产物 CapR 蛋白是一种 ATP 水解依赖性蛋白酶和非特异性核酸结合蛋白。它也是一种 DNA 刺激的 ATP 酶。这种新活性与蛋白酶相关的 ATP 酶活性不同，并且在不存在蛋白水解底物的情况下发生。该反应需要二价阳离子的存在，最适 pH 值为 8.0。反应产物是ADP和Pi。未检测到 DNA 或蛋白质的腺苷酸化或磷酸化。 ATP 水解的最大速率发生在超螺旋（I 型）DNA 存在的情况下。松弛环（形式 II）、双链 DNA 和单链 DNA 在促进 ATP 酶活性方面效果较差。 RNA 不活跃。 DNA 刺激的 ATP 酶活性被称为 CapR9 蛋白的 CapR 蛋白突变形式所抑制。 CapR 和 CapR9 亚基的相互作用表明，CapR 蛋白的酶活性在 DNA 存在的情况下是寡聚的。这些实验表明核酸在调节所有 lon (capR) 活性中可能发挥作用。
The gene product of the pleiotropic lon (also called capR) locus in Escherichia coli, the CapR protein, is an ATP hydrolysis-dependent protease and a nonspecific nucleic acid-binding protein. It is also a DNA-stimulated ATPase. This new activity is distinct from the protease-associated ATPase activity and occurred in the absence of proteolytic substrate. The reaction required the presence of a divalent cation and had a pH optimum of 8.0. The products of the reaction were ADP and Pi. No adenylation or phosphorylation of the DNA or proteins was detected. The maximum rate of ATP hydrolysis occurred in the presence of supercoiled (form I) DNA. Relaxed circles (form II), double-stranded DNA and single-stranded DNA were less effective in promoting ATPase activity. RNA was inactive. The DNA-stimulated ATPase activity was inhibited by a mutationally altered form of the CapR protein called the CapR9 protein. The interaction of the CapR and CapR9 subunits suggests that this enzymatic activity of the CapR protein is oligomeric in the presence of DNA. These experiments indicate a possible role for nucleic acids in the regulation of all lon (capR) activity.