Iron and zinc binding activity of Escherichia coli topoisomerase I homolog YrdD.
Iron and zinc binding activity of Escherichia coli topoisomerase I homolog YrdD.
复制标题
大肠杆菌拓扑异构酶 I 同源物 YrdD 的铁和锌结合活性
DOI：
10.1007/s10534-013-9698-z
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发表时间：
2014-04
期刊：
影响因子：
--
通讯作者：
Ding H
中科院分区：
文献类型：
--
作者：
Cheng Z;Tan G;Wang W;Su X;Landry AP;Lu J;Ding H
YrdD是大肠杆菌拓扑异构酶I c端锌结合区的同源物，在变形菌和肠杆菌中高度保守。然而，YrdD的功能仍然难以捉摸。在这里，我们报道从LB培养基中培养的大肠杆菌细胞中纯化的YrdD含有锌和铁。在培养基中补充外源锌可以消除大肠杆菌细胞中YrdD的铁结合，这表明铁和锌可能会竞争蛋白质中相同的金属结合位点。虽然锌结合的YrdD能够结合单链DNA并在体外保护ssDNA免受DNase I的消化，但铁结合的YrdD对ssDNA的结合活性非常低或没有，这表明锌结合的YrdD可能通过与细胞中的ssDNA相互作用在DNA修复中发挥重要作用。
YrdD, a homolog of the C-terminal zinc-binding region of Escherichia coli topoisomerase I, is highly conserved among proteobacteria and enterobacteria. However, the function of YrdD remains elusive. Here we report that YrdD purified from E. coli cells grown in LB media contains both zinc and iron. Supplement of exogenous zinc in the medium abolishes the iron binding of YrdD in E. coli cells, indicating that iron and zinc may compete for the same metal binding sites in the protein. While the zinc-bound YrdD is able to bind single-stranded (ss) DNA and protect ssDNA from the DNase I digestion in vitro, the iron-bound YrdD has very little or no binding activity for ssDNA, suggesting that the zinc-bound YrdD may have an important role in DNA repair by interacting with ssDNA in cells.