Heinzl Geoffrey A, Huang Weiliang, Yu Wenbo, Giardina Bennett J, Zhou Yue, MacKerell Alexander D, Wilks Angela, Xue Fengtian
University of Maryland Computer-Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland , Baltimore, Maryland 21201, United States.
J Med Chem. 2016 Jul 28;59(14):6929-42. doi: 10.1021/acs.jmedchem.6b00757. Epub 2016 Jul 11.
New therapeutic targets are required to combat multidrug resistant infections, such as the iron-regulated heme oxygenase (HemO) of Pseudomonas aeruginosa, due to links between iron and virulence and dependence on heme as an iron source during infection. Herein we report the synthesis and activity of a series of iminoguanidine-based inhibitors of HemO. Compound 23 showed a binding affinity of 5.7 μM and an MIC50 of 52.3 μg/mL against P. aeruginosa PAO1. An in cellulo activity assay was developed by coupling HemO activity to a biliverdin-IXα-dependent infrared fluorescent protein, in which compound 23 showed an EC50 of 11.3 μM. The compounds showed increased activity against clinical isolates of P. aeruginosa, further confirming the target pathway. This class of inhibitors acts by binding to an allosteric site; the novel binding site is proposed in silico and supported by saturation transfer difference (STD) NMR as well as by hydrogen exchange mass spectrometry (HXMS).
由于铁与毒力之间的联系以及感染期间对血红素作为铁源的依赖性,需要新的治疗靶点来对抗多重耐药感染,例如铜绿假单胞菌的铁调节血红素加氧酶(HemO)。在此,我们报告了一系列基于亚氨基胍的HemO抑制剂的合成及活性。化合物23对铜绿假单胞菌PAO1的结合亲和力为5.7 μM,MIC50为52.3 μg/mL。通过将HemO活性与依赖于胆绿素-IXα的红外荧光蛋白偶联,开发了一种细胞内活性测定方法,其中化合物23的EC50为11.3 μM。这些化合物对铜绿假单胞菌临床分离株的活性增强,进一步证实了目标途径。这类抑制剂通过结合变构位点发挥作用;通过计算机模拟提出了新的结合位点,并得到饱和转移差(STD)核磁共振以及氢交换质谱(HXMS)的支持。