Oct-1 POU domain DNA interactions: Cooperative binding of isolated subdomains and effects of covalent linkage
Oct-1 POU domain DNA interactions: Cooperative binding of isolated subdomains and effects of covalent linkage
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DOI：
10.1101/gad.10.1.27
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发表时间：
1996-01-01
影响因子：
10.5
通讯作者：
Pabo, CO
中科院分区：
文献类型：
--
作者：
Klemm, JD;Pabo, CO
Oct-1 POU结构域- dna相互作用的结构和生化研究提出了关于POU特异性结构域和POU同源结构域连接子的协同性和作用的重要问题。为了分析这些相互作用，我们研究了孤立结构域的结合。令人惊讶的是，我们发现POU特异性结构域和POU同源结构域对应的两个未连接多肽与八聚体位点协同结合，偶能为1.6 kcal/mol。我们认为，在Oct-1 POU结构域-DNA复合体的晶体结构中，结构域之间没有蛋白质-蛋白质的接触，因此在八聚体中心附近重叠的DNA接触可能是这种协同性的来源。这些研究也使我们能够根据有效浓度（3.6 mM）描述连接剂（存在于完整的POU域中）的热力学贡献。对理解蛋白质- dna识别和基因调控中的协同性的更广泛意义进行了讨论。
Structural and biochemical studies of Oct-1 POU domain-DNA interactions have raised important questions about cooperativity and the role of the linker connecting the POU-specific domain and the POU homeo domain. To analyze these interactions, we have studied binding of the isolated domains. Surprisingly, we find that two unlinked polypeptides corresponding to the POU-specific domain and the POU homeo domain bind cooperatively to the octamer site and have a coupling energy of 1.6 kcal/mole. We suggest that overlapping DNA contacts near the center of the octamer site may be the source of this cooperativity, as there are no protein-protein contacts between the domains in the crystal structure of the Oct-1 POU domain-DNA complex. These studies also have allowed us to describe the thermodynamic contribution of the linker (present in the intact POU domain) in terms of an effective concentration (3.6 mM). The broader implications for understanding cooperativity in protein-DNA recognition and gene regulation are discussed.