title: Identification and validation of a novel lead compound targeting 4-diphosphocytidyl-2-C-methylerythritol synthetase (IspD) of mycobacteria.
abstract: Tuberculosis is a serious threat to world-wide public health usually caused in humans by Mycobacterium tuberculosis (M. tuberculosis). It exclusively utilizes the methylerythritol phosphate (MEP) pathway for biosynthesis of isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP), the precursors of all isoprenoid compounds. The 4-diphosphocytidyl-2-C-methyl-D-erythritol synthase (IspD; EC 2.7.7.60) is the key enzyme of the MEP pathway. It is also of interest as a new chemotherapeutic target, as the enzyme is absent in mammals and ispD is an essential gene for growth. A high-throughput screening method was therefore developed to identify compounds that inhibit IspD. This process was applied to identify a lead compound, domiphen bromide (DMB), that may effectively inhibit IspD. The inhibitory action of DMB was confirmed by over-expressing or down-regulating IspD in Mycobacterium smegmatis (M. smegmatis), demonstrating that DMB inhibit M. smegmatis growth additionally through an IspD-independent pathway. This also led to higher levels of growth inhibition when combined with IspD knockdown. This novel IspD inhibitor was also reported to exhibit antimycobacterial activity in vitro, an effect that likely occurs as a result of perturbation of cell wall biosynthesis.
authors.affiliation: Department of Microbiology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Yang
authors.forename: Chunling
authors.initials: C
authors.lastname: Xiao
authors.forename: Yishuang
authors.initials: Y
authors.lastname: Liu
authors.forename: Maoluo
authors.initials: M
authors.lastname: Gan
authors.forename: Yan
authors.initials: Y
authors.lastname: Guan
authors.forename: Xueqin
authors.initials: X
authors.lastname: Hao
authors.forename: Jianzhou
authors.initials: J
authors.lastname: Meng
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhou
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Chen
authors.forename: Jiafei
authors.initials: J
authors.lastname: Cui
mesh_terms: D004353:Drug Evaluation, Preclinical; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D057166:High-Throughput Screening Assays; D007700:Kinetics; D020102:Mycobacterium smegmatis / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000201:enzymology*; D010088:Oxidoreductases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000302:isolation & purification; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D015203:Reproducibility of Results
chemical_list: D004791:Enzyme Inhibitors; D000644:Quaternary Ammonium Compounds; C007556:domiphen; D010088:Oxidoreductases