Shannon-Lowe Claire D, Emery Vincent C
Department of Infection, Centre for Virology, UCL (Royal Free Campus Campus), Rowland Hill Street, Hampstead, London NW3 2QG, UK.
Herpesviridae. 2010 Dec 7;1(1):4. doi: 10.1186/2042-4280-1-4.
The UL97 protein kinase of human cytomegalovirus phosphorylates the antiviral drug ganciclovir and is the target of maribavir action. A detailed enzyme kinetic analysis of maribavir on the various enzymatic functions of wild type and ganciclovir resistant forms of UL97 is required.
Wild type and site directed mutant forms of the human cytomegalovirus UL97 gene product were expressed using recombinant baculoviruses and the purified products used to assess the effects of maribavir on the ganciclovir (GCV) kinase and protein kinase (PK) activities.
Maribavir was a potent inhibitor of the autophosporylation of the wild type and all the major GCV resistant UL97 mutants analysed (M460I, H520Q, A594V and L595F) with a mean IC50 of 35 nM. The M460I mutation resulted in hypersensitivity to maribavir with an IC50 of 4.8 nM. A maribavir resistant mutant of UL97 (L397R) was functionally compromised as both a GCV kinase and a protein kinase (~ 10% of wild type levels). Enzyme kinetic experiments demonstrated that maribavir was a competitive inhibitor of ATP with a Ki of 10 nM.
Maribavir is a potent competitive inhibitor of the UL97 protein kinase function and shows increased activity against the M460I GCV-resistant mutant which may impact on the management of GCV drug resistance in patients.
人巨细胞病毒的UL97蛋白激酶可使抗病毒药物更昔洛韦磷酸化，是马里巴韦的作用靶点。需要对马里巴韦对野生型和更昔洛韦耐药型UL97的各种酶功能进行详细的酶动力学分析。
使用重组杆状病毒表达人巨细胞病毒UL97基因产物的野生型和定点突变形式，并使用纯化产物评估马里巴韦对更昔洛韦（GCV）激酶和蛋白激酶（PK）活性的影响。
马里巴韦是野生型以及所有分析的主要GCV耐药UL97突变体（M460I、H520Q、A594V和L595F）自身磷酸化的有效抑制剂，平均IC50为35 nM。M460I突变导致对马里巴韦超敏，IC50为4.8 nM。UL97的一个马里巴韦耐药突变体（L397R）作为GCV激酶和蛋白激酶的功能均受损（约为野生型水平的10%）。酶动力学实验表明，马里巴韦是ATP的竞争性抑制剂，Ki为10 nM。
马里巴韦是UL97蛋白激酶功能的有效竞争性抑制剂，对M460I GCV耐药突变体显示出增强的活性，这可能会影响患者中GCV耐药的管理。
