PCR-based development of DNA substrates containing modified bases: An efficient system for investigating the role of the exocyclic groups in chemical and structural recognition by minor groove binding drugs and proteins
PCR-based development of DNA substrates containing modified bases: An efficient system for investigating the role of the exocyclic groups in chemical and structural recognition by minor groove binding drugs and proteins
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DOI：
10.1073/pnas.93.24.13623
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发表时间：
1996-11-26
影响因子：
11.1
通讯作者：
Waring, MJ
中科院分区：
文献类型：
--
作者：
Bailly, C;Payet, D;Waring, MJ
含有肌苷代替鸟苷和/或2，6-二氨基嘌呤代替腺嘌呤的DNA分子已被合成，并被测试为用于结合小的和大的序列选择性配体的底物。足迹模式显示，AT-或CC-特异性抗生素（偏端霉素或光神霉素，分别）的结合位点完全改变的修饰的DNA，如预期的直接序列读出涉及接触嘌呤2-氨基。然而，我们也发现HMG-D（染色体蛋白质的HMG-1家族的成员）的结合发生了很大的变化，这表明环外氨基通过影响双螺旋的变形性对配体结合产生了间接影响。这种解释通过以下发现得到了证实：在大沟中缺乏胸苷的环外甲基的含脱氧尿苷的多核苷酸和寡核苷酸，与HMG-D的相互作用比含有天然核苷酸的对应物强5-10倍。
DNA molecules containing inosine in place of guanosine and/or 2,6-diaminopurine in place of adenine have been synthesized and tested as substrates for binding of sequence-selective ligands, both small and large. Footprinting patterns reveal that the binding sites for AT- or CC-specific antibiotics (distamycin or mithramycin, respectively) are completely changed in the modified DNAs, as expected for direct sequence readout involving contact with the purine 2-amino group. However, we also find large changes in the binding of HMG-D, a member of the HMG-1 family of chromosomal proteins, pointing to an indirect influence of the exocyclic amino group on ligand binding via an effect on the deformability of the double helix, This interpretation is confirmed by the finding that deoxyuridine-containing poly- and oligonucleotides, which lack the exocyclic methyl group of thymidine in the major groove, interact 5-10 times more strongly with HMG-D than do their counterparts containing natural nucleotides.