P53 BINDS SINGLE-STRANDED-DNA ENDS AND CATALYZES DNA RENATURATION AND STRAND TRANSFER
P53 BINDS SINGLE-STRANDED-DNA ENDS AND CATALYZES DNA RENATURATION AND STRAND TRANSFER
复制标题
DOI：
10.1073/pnas.91.1.413
复制
发表时间：
1994-01-04
影响因子：
11.1
通讯作者：
WIMAN, KG
中科院分区：
文献类型：
--
作者：
BAKALKIN, G;YAKOVLEVA, T;WIMAN, KG
肿瘤抑制蛋白p53先前已被证明能结合双链和单链DNA。我们报道p53蛋白可以结合单链DNA末端，催化DNA的再生和DNA链转移。细菌表达的野生型p53蛋白和谷胱甘肽s -转移酶野生型p53融合蛋白都能催化不同短（25- 76 nt）互补单链DNA片段的再生，并促进短（36-bp）双工DNA和互补单链DNA之间的链转移。从伯基特淋巴瘤的突变型p53基因中衍生出的携带氨基酸取代的突变型p53融合蛋白Glu-213、Ile-237或Tyr-238不能催化这些反应。在电泳迁移位移试验中，野生型p53对短链DNA片段（36- 76 nt）的结合亲和力明显高于对长链DNA片段（大于或等于462 nt）的结合亲和力。此外，电子显微镜显示p53优先结合单链DNA末端。DNA末端与p53寡聚物的结合可能允许互补链对齐。这些发现表明p53可能在DNA断裂的修复中起直接作用，包括互补单链DNA末端的连接。
The p53 tumor-suppressor protein has previously been shown to bind double-stranded and single-stranded DNA. We report that the p53 protein can bind single-stranded DNA ends and catalyze DNA renaturation and DNA strand transfer. Both a bacterially expressed wild-type p53 protein and a glutathione S-transferase-wild-type p53 fusion protein catalyzed renaturation of different short (25- to 76-nt) complementary single-stranded DNA fragments and promoted strand transfer between short (36-bp) duplex DNA and complementary single-stranded DNA. Mutant p53 fusion proteins carrying amino acid substitutions Glu-213, Ile-237, or Tyr-238, derived from mutant p53 genes of Burkitt lymphomas, failed to catalyze these reactions. Wild-type p53 had significantly higher binding affinity for short (36- to 76-nt) than for longer (greater-than-or-equal-to 462-nt) single-stranded DNA fragments in an electrophoretic mobility-shift assay. Moreover, electron microscopy showed that p53 preferentially binds single-stranded DNA ends. Binding of DNA ends to p53 oligomers may allow alignment of complementary strands. These findings suggest that p53 may play a direct role in the repair of DNA breaks, including the joining of complementary single-stranded DNA ends.