Weygand-Durasevic I, Susic S
Department of Organic Chemistry and Biochemistry, Faculty of Science, University of Zagreb, Yugoslavia.
Biochim Biophys Acta. 1990 Jan 30;1048(1):38-42. doi: 10.1016/0167-4781(90)90019-x.
Several DNA fragments deriving from plasmid pBR322 were used to determine the modification sites caused by the reaction with alkylating spin-labeling probes. At a high spin-label concentration, all guanines became alkylated, causing the cleavage of the phosphodiester bonds upon the treatment with piperidine. The lengths of the breakage products of 5'-end labeled DNA treated with spin labels were compared with the length of DNA scission products generated by Maxam-Gilbert procedure for DNA sequence analysis. The distribution of the guanine modifications is dependent on the amount of the reagent used for the alkylation and the ionic conditions of the reaction. The frequency of alkylation by spin labels was greatly enhanced within continuous runs of guanines in DNA. The stabilization of the DNA structure by magnesium or spermine directs the spin-label binding specifically to the most exposed region of DNA fragment containing GGTGG sequence. The sequence-dependent interaction of spin labels with DNA enables the development of the method for the selective spin labeling of DNA molecule.
使用了几个源自质粒pBR322的DNA片段来确定与烷基化自旋标记探针反应所导致的修饰位点。在高自旋标记浓度下，所有鸟嘌呤都被烷基化，在用哌啶处理后导致磷酸二酯键断裂。将用自旋标记处理的5'-末端标记DNA的断裂产物长度与用于DNA序列分析的Maxam-Gilbert方法产生的DNA断裂产物长度进行比较。鸟嘌呤修饰的分布取决于用于烷基化的试剂用量和反应的离子条件。在DNA中鸟嘌呤的连续排列中，自旋标记的烷基化频率大大提高。镁或精胺对DNA结构的稳定作用使自旋标记特异性地结合到含有GGTGG序列的DNA片段最暴露的区域。自旋标记与DNA的序列依赖性相互作用使得能够开发出对DNA分子进行选择性自旋标记的方法。
