Alden C J, Arnott S
Nucleic Acids Res. 1975 Oct;2(10):1701-17. doi: 10.1093/nar/2.10.1701.
A computerized linked-atom modeling system was developed to examine the stereochemical requirements for intercalation of planar drugs into DNA. All classes of conformational possibilities for extending the polynucleotide backbone were examined for their ability to accommodate insertion of a drug into a base-paired region of DNA compatible with adjacent regions of B-DNA while stacking interactions, steric strain and non-bonded interatomic contacts were optimised. One conformation was found which proved superior to all others in ability to satisfy these criteria: an extension of the backbone by characteristic changes in two torsion angles to trans values, plus a change in one sugar puckering to C3'-endo to relieve strain in an adjacent residue. The turn angle distributed over three polynucleotides for this most general mode of intercalation is 90 degrees, equivalent to a helical unwinding of -18 degrees for B-DNA.
开发了一种计算机化的连接原子建模系统,以研究平面药物插入DNA的立体化学要求。研究了多核苷酸主链延伸的所有构象可能性,以考察其在堆叠相互作用、空间应变和非键合原子间接触得到优化的情况下,将药物插入与B-DNA相邻区域兼容的DNA碱基对区域的能力。发现了一种构象,在满足这些标准的能力方面优于所有其他构象:主链通过两个扭转角的特征性变化延伸至反式值,加上一个糖环构象变为C3'-内向以缓解相邻残基的应变。这种最常见的嵌入模式在三个多核苷酸上分布的转角为90度,相当于B-DNA的螺旋解旋-18度。