| 论文题目: | Characterization of EndoTT, a novel single-stranded DNA specific endonuclease from Thermoanaerobacter tengcongensis |
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| 作者: | Shuli Zhang#, Bo Liu#, Haihua Yang*, Yuqing Tian, Gang Liu, Lei Li and Huarong Tan*. |
| 联系作者: | 谭华荣 |
| 刊物名称: | Nucleic Acids Research |
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| 年份: | 2010 |
| 影响因子: | 7.479 |
| 论文下载: | 下载地址 |
| 摘要: | EndoTT encoded by tte0829 of Thermoanaerobacter tengcongensis binds and cleaves single-stranded (ss) and damaged double-stranded (ds) DNA in vitro as well as binding dsDNA. In the presence of a low concentration of NaCl, EndoTT cleaved ss regions of damaged dsDNA efficiently but did not cleave DNA that was entirely ss or ds. At high concentrations of NaCl or MgCl2 or ATP, there was also specific cleavage of ssDNA. This suggested a preference for ss/ds junctions to stimulate cleavage of the DNA substrates. EndoTT has six specific sites (a–f) in the oriC region (1–70 nt) of T. tengcongensis. Substitutions of nucleotides around site c prevented cleavage by EndoTT of both sites c and d, implying that the cleavage specificity may depend on both the nucleotide sequence and the secondary structure of the ssDNA. A C-terminal sub-fragment of EndoTT (residues 107–216) had both endonucleolytic and DNA-binding activity, whereas an N-terminal sub-fragment (residues 1–110) displayed only ssDNA-binding activity. Site-directed mutations showed that G170, R172 and G177 are required for the endonuclease activity of EndoTT, but not for DNA-binding, whereas D171, R178 and G189 are partially required for the DNA-binding activity. |
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