Mapping the active-site tyrosine of vaccinia virus DNA topoisomerase I.
Mapping the active-site tyrosine of vaccinia virus DNA topoisomerase I.
复制标题
绘制痘苗病毒 DNA 拓扑异构酶 I 活性位点酪氨酸图谱。
DOI：
10.1073/pnas.86.24.9793
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发表时间：
1989
影响因子：
11.1
通讯作者：
Morham,SG
中科院分区：
文献类型：
--
作者：
Shuman,S;Kane,EM;Morham,SG
Site-directed mutagenesis of the vaccinia virus gene encoding a type I DNA topoisomerase implicates Tyr-274 as the active-site residue that forms a covalent adduct with DNA during cycles of DNA-strand breakage and reunion. Replacement of Tyr-274 by phenylalanine results in loss of the ability of the enzyme to relax negatively supercoiled DNA as well as to form the covalent DNA-protein intermediate. Substitution of phenylalanine for tyrosine at nine other sites in the protein has no apparent effect on enzyme activity. Amino acid sequence alignment reveals Tyr-274 to be homologous to Tyr-727 and Tyr-771, respectively, of the type I topoisomerases from Saccharomyces cerevisiae and Saccharomyces pombe; Tyr-727 and Tyr-771 have been shown to represent the active-site tyrosines of those enzymes. Sequence comparison of the active-site regions defines a motif Ser-Lys-Xaa-Xaa-Tyr common to the viral and cellular type I topoisomerases, including the human enzyme.
