From lin-Benzoguanines to lin-Benzohypoxanthines as Ligands for Zymomonas mobilis tRNA-Guanine Transglycosylase: Replacement of Protein-Ligand Hydrogen Bonding by Importing Water Clusters
作者:Luzi Jakob Barandun、Florian Immekus、Philipp C. Kohler、Sandro Tonazzi、Björn Wagner、Severin Wendelspiess、Tina Ritschel、Andreas Heine、Manfred Kansy、Gerhard Klebe、François Diederich
DOI:10.1002/chem.201200809
日期:2012.7.23
presence of an N‐alkyl group at C(6) in lin‐benzoguanine ligands, this water cluster is largely maintained but replacement of one of the water molecules in the cluster leads to a substantial loss in binding affinity. This study provides new insight into the role of water clusters at enzyme active sites and their challenging substitution by ligand parts, a topic of general interest in contemporary structure‐based
食源性志贺菌病是由分泌高细胞毒性志贺毒素的志贺氏菌引起的,志贺菌毒素也由密切相关的肠出血性大肠杆菌(EHEC)形成。研究表明,tRNA-鸟嘌呤转糖基酶(TGT)对于弗氏志贺氏菌的致病性至关重要。这里,在一个鸟嘌呤结合口袋的分子识别性能运动发酵单胞TGT与一系列调查林-benzohypoxanthine-和林基于-benzoguanine-抑制剂带有取代基占据任一核糖-33或核糖-34的口袋。这三种抑制剂支架的不同之处在于C(6)处的取代基为H,NH2或NH烷基。这些差异导致抑制常数,p K a值和结合模式发生重大变化。相较于林-benzoguanines,用环外NH 2在C(6)中,林-benzohypoxanthines无环外NH 2基团具有亲和力较弱几个离子蛋白质-配体的氢键都将丢失。X射线共晶体结构分析表明,由于缺少NH 2基团和催化Asp102侧链的构象转移,新的水簇被引入到空缺