Monaco R R, Hausheer F H
Univ of Texas, Dept of Chemistry, Austin 78712.
J Biomol Struct Dyn. 1993 Feb;10(4):675-80. doi: 10.1080/07391102.1993.10507999.
Molecular modeling of the system composed of ethidium cation initially intercalated through the major and minor grooves of the B-DNA form of 5'GCATGC3' into the central AT pairs, with the phenyl group oriented either toward or away from the helical axis, led upon energy minimization to intercalation complexes only when the phenyl group was initially oriented away from the helical axis. For the other two cases, energy minimization led to extrusion of the ethidium from the helix to form unanticipated outside-bound complexes stabilized by specific hydrogen bonds. It is suggested that outside-bound major groove complexes involving the GXXXG sequence may play important roles in the reaction mechanism of ethidium intercalation and in its action as a drug.
由最初通过5'GCATGC3'B - DNA形式的大沟和小沟插入到中心AT碱基对中的溴化乙锭阳离子组成的系统的分子模型，其中苯基要么朝向螺旋轴要么远离螺旋轴，在能量最小化时，只有当苯基最初远离螺旋轴时才形成插入复合物。对于其他两种情况，能量最小化导致溴化乙锭从螺旋中挤出，形成由特定氢键稳定的意外的外部结合复合物。有人提出，涉及GXXXG序列的外部结合大沟复合物可能在溴化乙锭插入的反应机制及其作为药物的作用中起重要作用。
