Tomkuvienė Miglė, Kriukienė Edita, Klimašauskas Saulius
Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
Adv Exp Med Biol. 2022;1389:535-562. doi: 10.1007/978-3-031-11454-0_19.
DNA methyltransferases (MTases) uniquely combine the ability to recognize and covalently modify specific target sequences in DNA using the ubiquitous cofactor S-Adenosyl-L-methionine (AdoMet). Although DNA methylation plays important roles in biological signaling, the transferred methyl group is a poor reporter and is highly inert to further biocompatible derivatization. To unlock the biotechnological power of these enzymes, extended cofactor AdoMet analogs have been developed that enable targeted MTase-directed attachment of larger moieties containing functional or reporter groups onto DNA. As the enlarged cofactors are not always compatible with the active sites of native MTases, steric engineering of the active site has been employed to optimize their alkyltransferase activity. In addition to the described cofactor analogs, recently discovered atypical reactions of DNA cytosine-5 MTases involving non-cofactor-like compounds can also be exploited for targeted derivatization and labeling of DNA. Altogether, these approaches offer new powerful tools for sequence-specific covalent DNA labeling, leading to a variety of useful techniques in DNA research, diagnostics and nanotechnologies, and have already proven practical utility for optical DNA mapping and high-throughput epigenome studies.
DNA甲基转移酶（MTases）具有独特的能力，即利用普遍存在的辅因子S-腺苷-L-甲硫氨酸（AdoMet）识别并共价修饰DNA中的特定靶序列。尽管DNA甲基化在生物信号传导中发挥着重要作用，但转移的甲基是一种不良的报告基团，并且对进一步的生物相容性衍生化具有高度惰性。为了释放这些酶的生物技术潜力，人们开发了扩展的辅因子AdoMet类似物，能够在MTase的靶向作用下，将含有功能基团或报告基团的更大基团连接到DNA上。由于增大的辅因子并不总是与天然MTases的活性位点兼容，因此人们采用活性位点的空间工程来优化它们的烷基转移酶活性。除了上述的辅因子类似物外，最近发现的DNA胞嘧啶-5 MTases涉及非辅因子样化合物的非典型反应，也可用于DNA的靶向衍生化和标记。总之，这些方法为序列特异性共价DNA标记提供了新的强大工具，催生了DNA研究、诊断和纳米技术中的各种有用技术，并且已经在光学DNA图谱绘制和高通量表观基因组研究中证明了实际效用。
