RECOGNITION OF THE SURFACE OF A HOMEO DOMAIN PROTEIN
RECOGNITION OF THE SURFACE OF A HOMEO DOMAIN PROTEIN
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DOI：
10.1101/gad.6.11.2047
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发表时间：
1992-11-01
影响因子：
10.5
通讯作者：
SHARP, PA
中科院分区：
文献类型：
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作者：
POMERANTZ, JL;KRISTIE, TM;SHARP, PA
同源结构域蛋白表现出独特的生物学功能，其特异性不能通过其结合DNA的序列特异性来预测。Oct-1 POU同源结构域表面的识别为选择性蛋白质-蛋白质相互作用对同源结构域因子家族的功能特异性的贡献提供了一般模型。Oct-1在单纯疱疹病毒α/IE增强子上组装成多蛋白复合物是由其同源结构域与辅助因子的相互作用指定的。该复合物（C1复合物）由病毒alphaTIF蛋白（VP 16）、Oct-1和一种额外的细胞组分C1因子组成。通过定点诱变产生Oct-1 POU同源结构域的变体，其改变了预测形成结构域-DNA复合物的暴露表面的残基。在Oct-1 POU同源结构域的螺旋1或2的表面上具有单个氨基酸取代的蛋白质形成C1复合物的能力降低。这些突变体在与alphaTIF的协同DNA结合试验中的行为表明，Oct-1 POU同源结构域主要由C1复合物中的alphaTIF识别。Oct-1的优先识别密切相关的Oct-2蛋白的螺旋1的表面上的一个残基的严重影响，因为这个残基的引入到Oct-2 POU同源结构域显着增强其形成C1复合物的能力。
Homeo domain proteins exhibit distinct biological functions with specificities that cannot be predicted by their sequence specificities for binding DNA. Recognition of the surface of the Oct-1 POU homeo domain provides a general model for the contribution of selective protein-protein interactions to the functional specificity of the homeo domain family of factors. The assembly of Oct-1 into a multiprotein complex on the herpes simplex virus alpha/IE enhancer is specified by the interactions of its homeo domain with ancillary factors. This complex (C1 complex) is composed of the viral alphaTIF protein (VP16), Oct-1, and one additional cellular component, the C1 factor. Variants of the Oct-1 POU homeo domain were generated by site-directed mutagenesis, which altered the residues predicted to form the exposed surface of the domain-DNA complex. Proteins with single amino acid substitutions on the surface of either helix 1 or 2 of the Oct-1 POU homeo domain had decreased abilities to form the C1 complex. The behavior of these mutants in a cooperative DNA-binding assay with alphaTIF suggested that the Oct-1 POU homeo domain is principally recognized by alphaTIF in the C1 complex. The preferential recognition of Oct-1 over the closely related Oct-2 protein is critically influenced by a single residue on the surface of helix 1 because the introduction of this residue into the Oct-2 POU homeo domain significantly enhanced its ability to form a C1 complex.