Dalhoff Christian, Lukinavicius Grazvydas, Klimasauskas Saulius, Weinhold Elmar
Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52056 Aachen, Germany.
Nat Protoc. 2006;1(4):1879-86. doi: 10.1038/nprot.2006.253.
Here we describe a one-step synthetic procedure for the preparation of S-adenosyl-L-methionine (AdoMet) analogs with extended carbon chains replacing the methyl group. These AdoMet analogs function as efficient cofactors for DNA methyltransferases (MTases), and we provide a protocol for sequence-specific transfer of extended side chains from these AdoMet analogs to DNA by DNA MTases. Direct chemoselective allylation or propargylation of S-adenosyl-L-homocysteine (AdoHcy) at sulfur is achieved under the acidic conditions needed to protect other nucleophilic positions in AdoHcy. The unsaturated bonds in beta position to the sulfonium center of the resulting AdoMet analogs are designed to stabilize the transition state formed upon DNA MTase-catalyzed nucleophilic attack at the carbon next to the sulfonium center and lead to efficient transfer of the extended side chains to DNA. Using these protocols, sequence-specific functionalized DNA can be obtained within one to two weeks.
在此，我们描述了一种一步合成法，用于制备以延长碳链取代甲基的S-腺苷-L-甲硫氨酸（AdoMet）类似物。这些AdoMet类似物可作为DNA甲基转移酶（MTases）的有效辅因子，并且我们提供了一种方案，用于通过DNA MTases将延长侧链从这些AdoMet类似物序列特异性转移至DNA。在保护AdoHcy中其他亲核位点所需的酸性条件下，可实现S-腺苷-L-高半胱氨酸（AdoHcy）在硫原子处的直接化学选择性烯丙基化或炔丙基化。所得AdoMet类似物的锍中心β位的不饱和键旨在稳定DNA MTase催化在锍中心旁的碳原子处进行亲核攻击时形成的过渡态，并导致延长侧链高效转移至DNA。使用这些方案，可在一至两周内获得序列特异性功能化的DNA。
