Implication of RNase H domain on dimer stability and drug sensitivity of HIV-1 RT

描述(申请人提供)：HIV-1RT的连接亚域和RNaseH结构域最近被认为与对NRTI和NNRTI药物耐药的HIV-1毒株的出现有关。连接亚区和RNaseH结构域的定点突变据报道影响底物或NRTI结合亲和力和其他聚合酶相关的特性，如加工性，这表明在聚合酶结构域和HIV-1RT的这两个遥远的结构单元之间发生了确定的长距离串扰。许多机制，包括RNaseH裂解活性的降低，减少了模板切换，以及模板-引物底物的不正确定位，都被提出来解释耐药突变。基于HIV-1 RT的三维结构，我们认为RNaseH结构域与C-末端连接亚域相互作用的C-末端区域的疏水残基在亚单位二聚化过程中可能在结构上是重要的；这些区域的任何突变都可能影响HIV-1 RT的二聚体稳定性和底物结合亲和力。我们建议研究HIV-1RT连接亚区和RNaseH结构域界面疏水残基突变对酶的二聚体稳定性和药物敏感性的影响。我们还将包括与临床相关的耐药突变和在药物压力下出现的RNaseH。

DESCRIPTION (provided by applicant): The connection subdomain and RNase H domain of HIV-1 RT have recently been implicated in the emergence of HIV-1 strains that are resistant to NRTI and NNRTI drugs. Site-specific mutations in the connection subdomain and RNase H domain reportedly affect substrate or NRTI binding affinity and other polymerase-related properties such as processivity, suggesting that definitive long-distance cross-talk occurs between the polymerase domain and these two distantly located structural units of HIV-1 RT. Numerous mechanisms, including a reduction in RNase H cleavage activity, which decreased template switching, and improper positioning of template-primer substrate have been proposed to explain the drug-resistant mutations. Based on the three-dimensional (3D) structure of HIV-1 RT, we propose that hydrophobic residues at the C-terminal region of the RNase H domain interacting with the C-terminal connection subdomain may be structurally important in subunit dimerization; any mutational changes in these regions may affect dimer stability and the substrate binding affinity of HIV-1 RT. We propose to investigate the implications of mutations of hydrophobic residues at the interface of the connection subdomain and RNase H domain of HIV-1 RT with respect to dimer stability and drug sensitivity of the enzyme. We will also include clinically relevant drug-resistant mutations that emerge in connection and RNase H under drug pressure.