Crystal structure of poliovirus 3CD protein: Virally encoded protease and precursor to the RNA-dependent RNA polymerase
Crystal structure of poliovirus 3CD protein: Virally encoded protease and precursor to the RNA-dependent RNA polymerase
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DOI：
10.1128/jvi.02306-06
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发表时间：
2007-04-01
影响因子：
5.4
通讯作者：
Hogle, James M.
中科院分区：
文献类型：
--
作者：
Marcotte, Laura L.;Wass, Amanda B.;Hogle, James M.
脊髓灰质炎病毒3CD是一种多功能蛋白，作为蛋白酶3C（pro）和病毒聚合酶3D（pol）的前体，也在控制病毒复制中发挥作用。虽然3CD是一种功能齐全的蛋白酶，但它缺乏聚合酶活性。我们已经解决了晶体结构的3CD在3.4埃的分辨率和G64S保真度突变体的3D（pol）在3.0埃的分辨率。在3CD结构中，3C和3D结构域通过有序性差的多肽接头连接，可能是为了促进其切割，以排除分子内蛋白水解的排列。聚合酶活性位点在3CD和3D（pol）G64S结构中是完整的，尽管提出将关键残基定位在活性位点中的网络被破坏。因此，分子柔性的变化可能是保真度和聚合酶活性差异的原因。广泛的包装之间的接触与病毒相关的3CD分子和方法的3C结构域的N末端的VPg结合位点表明3D（pol）如何与3C，3CD，和3BCD蛋白，控制在病毒复制的启动VPg的尿苷酰化生物相关的相互作用。事实上，设计破坏这些接口的突变在体外对尿苷酰化反应有明显的影响。
Poliovirus 3CD is a multifunctional protein that serves as a precursor to the protease 3C(pro) and the viral polymerase 3D(pol) and also plays a role in the control of viral replication. Although 3CD is a fully functional protease, it lacks polymerase activity. We have solved the crystal structures of 3CD at a 3.4-angstrom resolution and the G64S fidelity mutant of 3D(pol) at a 3.0-angstrom resolution. In the 3CD structure, the 3C and 3D domains are joined by a poorly ordered polypeptide linker, possibly to facilitate its cleavage, in an arrangement that precludes intramolecular proteolysis. The polymerase active site is intact in both the 3CD and the 3D(pol) G64S structures, despite the disruption of a network proposed to position key residues in the active site. Therefore, changes in molecular flexibility may be responsible for the differences in fidelity and polymerase activities. Extensive packing contacts between symmetry-related 3CD molecules and the approach of the 3C domain's N terminus to the VPg binding site suggest how 3D(pol) makes biologically relevant interactions with the 3C, 3CD, and 3BCD proteins that control the uridylylation of VPg during the initiation of viral replication. Indeed, mutations designed to disrupt these interfaces have pronounced effects on the uridylylation reaction in vitro.