Hacker Hans Jörg, Deres Karl, Mildenberger Maria, Schröder Claus H
Department of Virus-Host Interactions (F0600), Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.
Biochem Pharmacol. 2003 Dec 15;66(12):2273-9. doi: 10.1016/j.bcp.2003.08.001.
Recently, heteroarylpyrimidines (HAP) have been identified as potent inhibitors of capsid maturation. Here we discuss the HAP mode of action comparing the aggregation phenotype of wild-type and mutant core proteins with the respective phenotype imposed by HAP or other agents interacting with core protein. Pertinent tests include core fusion protein-mediated transactivation in a two-hybrid system and capsid formation. The finding that transactivation appeared to be unaffected by HAP, or by mutations preventing assembly, is surprising and raises the question for the structure of the interacting hybrid core proteins: Are they monomers, dimers or even oligomers? A direct activity of core fusion monomers is not excluded but considered to be highly unlikely due to rapid homodimerisation. A role of core fusion dimers in transactivation would indicate distinct interactions with a differential sensitivity to HAP. Regarding significance of data gained in two-hybrid systems, caution is necessary, since the site of transactivation is the nucleus, whereas the real site of the core protein interactions during replication is the cytoplasm. Apparently, HAP leave the monomer-monomer interface of HBV core protein unaffected but prevent capsid maturation by interacting with a region known to be crucial for dimer multimerisation and formation of stable capsids. It is suggested to use antivirals as tools for the elucidation of early steps in genome replication and capsid assembly. A frame for this could be the hypothesis that the virus uses soluble core protein, namely intracellular maturation intermediates of HbeAg for a core targeted self-restriction of replication.
最近，杂芳基嘧啶（HAP）已被确定为衣壳成熟的有效抑制剂。在此，我们讨论HAP的作用模式，比较野生型和突变核心蛋白的聚集表型与由HAP或其他与核心蛋白相互作用的试剂所施加的相应表型。相关测试包括双杂交系统中核心融合蛋白介导的反式激活和衣壳形成。反式激活似乎不受HAP或阻止组装的突变影响，这一发现令人惊讶，并引发了关于相互作用的杂合核心蛋白结构的问题：它们是单体、二聚体还是甚至寡聚体？不排除核心融合单体的直接活性，但由于快速同源二聚化，认为其可能性极小。核心融合二聚体在反式激活中的作用将表明与对HAP具有不同敏感性的独特相互作用。关于在双杂交系统中获得的数据的意义，需要谨慎，因为反式激活的位点是细胞核，而复制过程中核心蛋白相互作用的实际位点是细胞质。显然，HAP不会影响乙肝病毒核心蛋白的单体 - 单体界面，但通过与已知对二聚体多聚化和稳定衣壳形成至关重要的区域相互作用来阻止衣壳成熟。建议使用抗病毒药物作为阐明基因组复制和衣壳组装早期步骤的工具。对此的一个框架可以是这样的假设，即病毒使用可溶性核心蛋白，即HbeAg的细胞内成熟中间体，对核心进行靶向自我复制限制。
