Lesion-specific DNA-binding and repair activities of human O⁶-alkylguanine DNA alkyltransferase.
Lesion-specific DNA-binding and repair activities of human O⁶-alkylguanine DNA alkyltransferase.
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人 O⁶-烷基鸟嘌呤 DNA 烷基转移酶的损伤特异性 DNA 结合和修复活性。
DOI：
10.1093/nar/gks674
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发表时间：
2012-10
影响因子：
14.9
通讯作者：
Fried MG
中科院分区：
文献类型：
--
作者：
Melikishvili M;Fried MG
对人 O6-烷基鸟嘌呤 DNA 烷基转移酶 (AGT) 的烷基转移活性和失活突变体进行的结合实验表明，它在双链 DNA 上形成 O6-甲基鸟嘌呤 (6mG) 特异性复合物，该复合物与之前研究的非特异性组装体不同。具有双链 DNA 的特定复合物具有 2:1 化学计量，形成时不会积累 1:1 中间体。这确立了病变结合中合作相互作用的作用。单链 DNA 无法检测到类似的特异性复合物。特异性和非特异性结合亲和力之间的微小差异强烈限制了特异性结合在病变搜索过程中可以发挥的作用。单链底物的烷基转移动力学表明两个或多个 AGT 单体参与限速步骤，首次显示了协同结合和修复反应之间的功能联系。双链体底物的烷基转移动力学表明，有两种途径有助于形成特定的 6mG 复合物：至少 AGT 中的一阶，我们将其解释为直接病变结合。第二个独立于[AGT]，可能包括以相对缓慢的单分子步骤将AGT从远端部位转移到病变处。我们认为远端和病变部位之间的转移是修复过程中的关键步骤。
Binding experiments with alkyl-transfer-active and -inactive mutants of human O6-alkylguanine DNA alkyltransferase (AGT) show that it forms an O6-methylguanine (6mG)-specific complex on duplex DNA that is distinct from non-specific assemblies previously studied. Specific complexes with duplex DNA have a 2:1 stoichiometry that is formed without accumulation of a 1:1 intermediate. This establishes a role for cooperative interactions in lesion binding. Similar specific complexes could not be detected with single-stranded DNA. The small difference between specific and non-specific binding affinities strongly limits the roles that specific binding can play in the lesion search process. Alkyl-transfer kinetics with a single-stranded substrate indicate that two or more AGT monomers participate in the rate-limiting step, showing for the first time a functional link between cooperative binding and the repair reaction. Alkyl-transfer kinetics with a duplex substrate suggest that two pathways contribute to the formation of the specific 6mG-complex; one at least first order in AGT, we interpret as direct lesion binding. The second, independent of [AGT], is likely to include AGT transfer from distal sites to the lesion in a relatively slow unimolecular step. We propose that transfer between distal and lesion sites is a critical step in the repair process.
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影响因子：
4.8
作者：
Geng, Hui;Sakato, Miho;Hsieh, Peggy
通讯作者：
Hsieh, Peggy
影响因子：
16.8
作者：
Daniels, DS;Woo, TT;Tainer, JA
通讯作者：
Tainer, JA
DOI：
10.1038/nrc3185
发表时间：
2012-01-12
期刊：
Nature reviews. Cancer
影响因子：
--
作者：
通讯作者：
--
影响因子：
14.9
作者：
Bender, K;Federwisch, M;Rajewsky, MF
通讯作者：
Rajewsky, MF
影响因子：
14.9
作者：
BADING, H
通讯作者：
BADING, H