Piret Jocelyne, Boivin Guy
Research Center of the CHU de Quebec-Laval University, Quebec City, QC G1V 4G2, Canada.
Department of Pediatrics, Faculty of Medicine, Laval University, Quebec City, QC G1V 0A6, Canada.
Viruses. 2025 Jul 2;17(7):941. doi: 10.3390/v17070941.
Infections with cytomegalovirus (CMV) can result in increased morbidity and mortality in immunocompromised patients. The pUL97 kinase is a critical enzyme in the regulation of CMV replication. Although it does not phosphorylate deoxynucleosides, this enzyme is involved in the first phosphorylation step of ganciclovir (GCV), a viral DNA polymerase inhibitor. In contrast, maribavir (MBV) is a specific inhibitor of pUL97 kinase activity. In this paper, we analyzed the already-reported amino acid changes, conferring resistance to MBV and cross-resistance to GCV, in the pUL97 protein structure, predicted with AlphaFold2. Docking experiments suggest that MBV is a dual-site inhibitor, targeting ATP binding and substrate phosphorylation. Substitutions that confer resistance to MBV only may directly or indirectly alter the shape of the cavity in the vicinity of the invariant K355 in the putative ATP binding site, without affecting the viral growth. The most frequently encountered T409M substitution may correspond to a gatekeeper mutation. Substitutions that induce cross-resistance to MBV and GCV may directly or indirectly affect the environment of D456 and N461 residues in the catalytic loop, with reduced viral replicative capacity. These results have implications for the clinical use of MBV as well as for the design of novel pUL97 kinase inhibitors.
巨细胞病毒（CMV）感染可导致免疫功能低下患者的发病率和死亡率增加。pUL97激酶是调节CMV复制的关键酶。虽然它不使脱氧核苷磷酸化，但该酶参与了更昔洛韦（GCV，一种病毒DNA聚合酶抑制剂）的第一步磷酸化反应。相比之下，马立巴韦（MBV）是pUL97激酶活性的特异性抑制剂。在本文中，我们分析了已报道的在通过AlphaFold2预测的pUL97蛋白结构中赋予对MBV耐药性和对GCV交叉耐药性的氨基酸变化。对接实验表明，MBV是一种双位点抑制剂，靶向ATP结合和底物磷酸化。仅赋予对MBV耐药性的替代可能直接或间接改变假定ATP结合位点中不变的K355附近腔的形状，而不影响病毒生长。最常见的T409M替代可能对应于守门人突变。诱导对MBV和GCV交叉耐药性的替代可能直接或间接影响催化环中D456和N461残基的环境，同时降低病毒复制能力。这些结果对MBV的临床应用以及新型pUL97激酶抑制剂的设计具有重要意义。
