Selective hits for the glutaredoxin ortholog of Brucella melitensis are determined using STD NMR and verified by trNOE and 15N-HSQC titration. The most promising hit, RK207, was docked into the target molecule using a scoring function to compare simulated poses to experimental data. After elucidating possible poses, the hit was further optimized into the lead compound by extension with an electrophilic acrylamide warhead. We believe that focusing on selectivity in this early stage of drug discovery will limit cross-reactivity that might occur with the human ortholog as the lead compound is optimized. Kinetics studies revealed that lead compound 5 modified with an ester group results in higher reactivity than an acrylamide control; however, after modification this compound shows little selectivity for bacterial protein versus the human ortholog. In contrast, hydrolysis of compound 5 to the acid form results in a decrease in the activity of the compound. Together these results suggest that more optimization is warranted for this simple chemical scaffold, and opens the door for discovery of drugs targeted against glutaredoxin proteins—a heretofore untapped reservoir for antibiotic agents.
针对布鲁氏菌梅利滕斯的
谷胱甘肽还原酶同源物的选择性命中通过STD NMR确定,并通过trNOE和15N-HSQC滴定进行了验证。最有前途的命中物RK207被使用评分函数对接到目标分子上,以将模拟构象与实验数据进行比较。在阐明可能的构象后,该命中物通过与电亲性
丙烯酰胺战斗头的扩展进一步优化为领先化合物。我们相信,在药物发现的早期阶段专注于选择性,将限制在优化领先化合物时可能与人类同源物发生的交叉反应性。动力学研究揭示,修饰有酯基的领先化合物5的反应性高于
丙烯酰胺对照;然而,在修饰后,该化合物对细菌蛋白相较于人类同源物显示出很少的选择性。相比之下,将化合物5
水解为酸性形式导致该化合物活性降低。这些结果表明,这种简单的
化学框架需要更多的优化,并为发现针对
谷胱甘肽还原酶蛋白的药物开辟了新途径——这之前未被开发的抗生素剂库。