Vishwanatha J K, Tauer T J, Rhode S L
Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, USA.
Mol Cell Biochem. 1995 May 24;146(2):121-6. doi: 10.1007/BF00944604.
A single-stranded DNA-dependent ATPase activity, consisting of two subunits of 83 kDa (p90) and 68 kDa (p70), was previously purified from HeLa cells (Vishwanatha, J.K. and Baril, E.F. (1990) Biochem 29, 8753-8759). Homology of the two subunits of single-stranded DNA-dependent ATPase with the human Ku protein (Cao et al. (1994) Biochem 33, 8548-8557) and identity of the Ku protein as the human DNA helicase II (Tuteja et al. (1994) EMBO J. 13, 4991-5001) have been reported recently. Using antisera raised against the subunits of the HDH II, we confirm that the Hela single-stranded DNA-dependent ATPase is the HDH II. Similar to the activity reported for Ku protein, ssDNA-dependent ATPase binds to double-stranded DNA and the DNA-protein complex detected by gel mobility shift assay consists of both the ATPase subunits. The p90 subunit is predominantly nuclear and is easily dissociated from chromatin. The p70 is distributed in cytosol and nucleus, and a fraction of the nuclear p70 protein is found to be associated with the nuclear matrix. Both the p90 and p70 subunits of the ATPase are present in G1 and S phase of the cell cycle and are rapidly degraded in the G2/M phase of the cell cycle.
一种单链DNA依赖性ATP酶活性，由83 kDa（p90）和68 kDa（p70）的两个亚基组成，先前已从HeLa细胞中纯化出来（Vishwanatha, J.K.和Baril, E.F.（1990年）《生物化学》29卷，8753 - 8759页）。单链DNA依赖性ATP酶的两个亚基与人Ku蛋白的同源性（Cao等人（1994年）《生物化学》33卷，8548 - 8557页）以及Ku蛋白作为人DNA解旋酶II的同一性（Tuteja等人（1994年）《欧洲分子生物学组织杂志》13卷，4991 - 5001页）最近已有报道。使用针对HDH II亚基产生的抗血清，我们证实HeLa单链DNA依赖性ATP酶就是HDH II。与报道的Ku蛋白活性相似，ssDNA依赖性ATP酶与双链DNA结合，凝胶迁移率变动分析检测到的DNA - 蛋白质复合物由两个ATP酶亚基组成。p90亚基主要存在于细胞核中，并且很容易从染色质上解离。p70分布在细胞质和细胞核中，并且发现一部分细胞核中的p70蛋白与核基质相关。ATP酶的p90和p70亚基在细胞周期的G1期和S期都存在，并且在细胞周期的G2/M期迅速降解。
