Lee M, Hartley J A, Pon R T, Krowicki K, Lown J W
Department of Chemistry, University of Alberta, Edmonton, Canada.
Nucleic Acids Res. 1988 Jan 25;16(2):665-84. doi: 10.1093/nar/16.2.665.
All 1H-NMR resonances of d-[CATGGCCATG]2 and the 1:1 complex of lexitropsin 1 and the DNA were assigned by the NOE difference, COSY and NOESY methods. Addition of 1 causes the base and imino protons for the sequence 5'-CCAT to undergo the most marked drug-induced chemical shift changes, thereby indicating that 1 is located in this base pair sequence. NOEs confirmed the location and orientation of the drug in the 1:1 complex, with the amino terminus oriented to C(6). The van der Waals interaction between H12a,b of 1 and AH2(8) may be responsible for reading of the 3' A.T base pair in the 5'-CCAT sequence. Exchange NMR effects allow an estimate of approximately equal to 62 s-1 for the intramolecular "slide-swing" exchange of the lexitropsin between two equivalent binding sites with delta G = 58 +/- 5 kJ mol-1 at 301 degrees K.
通过NOE差值、COSY和NOESY方法对d-[CATGGCCATG]2以及lexitropsin 1与DNA的1:1复合物的所有1H-NMR共振进行了归属。加入1会使5'-CCAT序列的碱基和亚氨基质子发生最显著的药物诱导化学位移变化，从而表明1位于该碱基对序列中。NOE证实了药物在1:1复合物中的位置和取向，氨基末端朝向C(6)。1的H12a、b与AH2(8)之间的范德华相互作用可能负责识别5'-CCAT序列中的3'A.T碱基对。交换NMR效应使得能够估计在301K时，lexitropsin在两个等效结合位点之间的分子内“滑动-摆动”交换速率约为62 s-1，ΔG = 58±5 kJ mol-1。
