Altered fidelity of a nucleic acid modifying enzyme, T4 polynucleotide kinase, by safrole-induced DNA damage.
Altered fidelity of a nucleic acid modifying enzyme, T4 polynucleotide kinase, by safrole-induced DNA damage.
复制标题
黄樟素诱导的 DNA 损伤改变了核酸修饰酶 T4 多核苷酸激酶的保真度。
DOI：
10.1093/carcin/14.8.1523
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发表时间：
1993
期刊：
影响因子：
4.7
通讯作者：
vanGolen,KL
中科院分区：
文献类型：
--
作者：
Randerath,K;Gupta,KP;vanGolen,KL
Mouse liver DNA adducted with metabolites of the spice constituent safrole (1-allyl-3, 4-methylenedioxybenzene), when analyzed via the bisphosphate version of the32P-postlabeling assay, exhibits two major adducts, which had been previously identified asN2-(trans-isosafrol-3' -yl)2' -deoxyguanosine 3', 5'-bisphosphate (adduct 1) andN2(safrol-1'-yl)2'-deoxyguanosine 3', 5'-bisphosphate (adduct 2). However, analysis of the same DNA preparation by the dinucleotide/monophosphate version of the assay gave two additional spots on PEI-ceihilose TLC whose nature was clarified in the present study. Several enzymes (T4 polynucleotide kinase, nuclease P1, venom phosphodiesterase and spleen phosphodiesterase) were utilized to hydrolyze these compounds, and the products co-chromatographed on PEI-cellulose thin layers with radiolabeled and non-radioactive nucleotides of known structure. The additional spots were found to be adducted dinucleotides carrying32P-label at both the 5'- and 3'-hydroxyls. T4 polynucleotide kinase-catalyzed 3'-phosphorylation was highly specific in that only dinucleoside monophosphate derivatives of adduct 1, with an unmodified purine in the 3'-position, were susceptible to both 5'- and 3'-phosphorylation by the enzyme. Thus, the structures of the two additional32P-labeled safrole derivatives were pX1pAp and pX1pGp where X1denotesN2-(trans-isosafrol-3'-yI)2'-deoxyguanosine. The official name of T4 polynucleotide kinase, ATP: 5'-dephosphopolynucleotide 5'-phosphotransferase (EC 2.7.1.78), denotes the specific action of this enzyme as a 5'-phosphokinase. Although the enzyme has 3'-phosphatase activity at acidic pH, no 3'-kinase reaction has been previously reported. Possible implications for chemical carcinogenesis of the finding that carcinogen - DNA adducts can specifically alter the fidelity of protein-nucleotide interactions are discussed.
