Maribavir (GW257406X) is an orally available benzimidazole riboside compound with activity against cytomegalovirus (CMV). Maribavir is a selective ATP competitor of the viral UL97 kinase, which is involved in viral nuclear maturation events, such as viral DNA assembly and movement of viral capsids from the nucleus of infected cells. Maribavir has activity against strains of CMV that are resistant to standard anti-CMV agents.

Histone phosphorylation:3 nM

Maribavir是一种强效的抑制剂，能够有效抑制野生型及所有主要的Ganciclovir（GCV）耐药UL97突变体的自磷酸化，平均IC50值为35 nM。M460I突变体对Maribavir表现出超敏感性，IC50值为4.8 nM。Maribavir耐药的UL97突变体（L397R）在功能上受到损害，无论作为Ganciclovir激酶还是蛋白激酶的表现都大大降低（约为野生型的10%）。酶动力学实验表明，Maribavir是ATP的竞争性抑制剂，Ki值为10 nM[1]。Maribavir（1263W94）能够以剂量依赖的方式抑制病毒复制，通过多周期DNA杂交分析测得的IC50为0.12±0.01 μM。pUL97蛋白激酶被Maribavir强烈抑制，50%抑制浓度为3 nM[2]。

Enzyme kinetic analysis is performed on the purified wild type and mutant UL97 protein species using increasing concentrations of ATP (2 μM to 20 μM). The amount of incorporated radiolabelled phosphate is plotted against the concentration of ATP in a Lineweaver Burke plot to determine the Km for ATP for each UL97 species. The effect of Maribavir upon the rate of radiolabelled phosphate incorporation by wild type or mutant UL97 is determined by protein kinase assays at a fixed concentration of Maribavir (0.5 μM) as above, or with increasing concentrations of Maribavir (0.01 μM to 5.0 μM) to determine the IC50 of Maribavir for each UL97 species. In order to determine the nature of the inhibition mediated by Maribavir, plots of 1/v vs 1/ATP with increasing concentrations of Maribavir are constructed. Competitive inhibition is evident if the family of lines cconverged on the y-axis at 1/Vmax. The change in slope caused by the addition of Maribavir is used to calculate the Ki[1].

Maribavir (1263W94) is dissolved in DMSO and stored, and then diluted with appropriate media before use[2]. For these studies MRC-5 cells are seeded in 24-well plates at ~5×104 cells/well and grown for 3 days in MEM 8-1-1 to confluence (~1.1×105 cells/well). The cells are infected with AD169 in MEM 2-1-1 at an MOI ranging from 1 to 3 and incubated at 37°C for 90 min to allow viral adsorption. The unadsorbed virus is removed and replaced with 1 mL of MEM 2-1-1. To test the effect of compounds on viral DNA synthesis or maturation, Maribavir, BDCRB, or GCV is added to the medium at the concentrations indicated for each experiment[2].