Occupying a flat subpocket in a tRNA-modifying enzyme with ordered or disordered side chains: Favorable or unfavorable for binding?
作者:Manuel Neeb、Christoph Hohn、Frederik Rainer Ehrmann、Adrian Härtsch、Andreas Heine、François Diederich、Gerhard Klebe
DOI:10.1016/j.bmc.2016.07.053
日期:2016.10
series of congeneric ligands inhibiting the tRNA-modifying enzyme TGT. Attached to the parent lin-benzoguanine scaffold, substituents in position 2 accommodate in a flat solvent-exposed pocket and exhibit varying degree of residual mobility. This is indicated in the crystal structures by enhanced B-factors, reduced occupancies, or distributions over split conformers. MD simulations of the complexes suggest
就其结合性能而言,通常认为具有部分无序或增强的残留迁移率的小分子配体是不利的。考虑到热力学,无序或残余迁移率在熵上是有利的,并有助于吉布斯结合能。在本研究中,我们分析了一系列抑制tRNA修饰酶TGT的同类配体。附在亲林-苯并鸟嘌呤支架,位置2的取代基容纳在暴露于溶剂的平坦袋中,并显示出不同程度的残留迁移率。这在晶体结构中通过增强的B因子,减少的占有率或在分裂构象异构体上的分布来表明。配合物的MD模拟表明,在几个构象族上的散射更大。末端酸性基团的引入通过盐桥将取代基固定至Arg残基。总的来说,所有取代的衍生物都显示出相同的亲和力,即顺序和无序性都不是结合亲和力的决定性因素。额外的盐桥保持强烈的溶剂接触,因此不会增加亲和力。医师建议这种接触是暂时性的。