Fluorescent stilbazolium dyes as probes of the norepinephrine transporter: structural insights into substrate binding
作者:James N. Wilson、Adrienne S. Brown、W. Michael Babinchak、Clark D. Ridge、Jamie D. Walls
DOI:10.1039/c2ob26633d
日期:——
We report the synthesis, binding kinetics, optical spectroscopy and predicted binding modes of a series of sterically demanding, fluorescent norepinephrine transporter (NET) ligands. A series of bulky stilbazolium dyes, including six newly synthesized compounds, were evaluated to determine the effect of extending the molecular probes’ ‘heads’ or ‘tails’. Taking advantage of the dyes’ characteristic ‘turn-on’ emission, the kinetic binding parameters, kon and koff were determined revealing that extension of the molecules’ tails is well tolerated while expansion of the head is not. Additionally, a ‘headfirst’ orientation appears to be preferred over a ‘tail-first’ binding pose. Further details of the possible binding modes were obtained from the emission spectra of the bound probes. A small range of interplanar twist angles, approximately 35° to 60°, is predicted to produce the observed emission. Docking experiments and molecular modelling support the kinetic and spectroscopic data providing structural insights into substrate binding.
我们报告了一系列立体要求苛刻的荧光去甲肾上腺素转运体(NET)配体的合成、结合动力学、光学光谱和预测结合模式。对包括六种新合成化合物在内的一系列笨重的链脲染料进行了评估,以确定延长分子探针 "头部 "或 "尾部 "的效果。利用染料特有的 "开启 "发射特性,确定了动力学结合参数 kon 和 koff,结果表明,分子尾部的扩展具有良好的耐受性,而头部的扩展则没有耐受性。此外,"头先 "方向似乎比 "尾先 "结合姿势更受青睐。从结合探针的发射光谱中可以进一步了解可能的结合模式。据预测,大约 35° 至 60° 的小范围平面间扭转角会产生观察到的发射。对接实验和分子建模支持动力学和光谱数据,为底物结合提供了结构性见解。