Principles of ligand binding within a completely buried cavity in HIF2alpha PAS-B.
Principles of ligand binding within a completely buried cavity in HIF2alpha PAS-B.
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DOI：
10.1021/ja9073062
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发表时间：
2009-12-09
影响因子：
15
通讯作者：
Gardner, Kevin H.
中科院分区：
文献类型：
--
作者：
Key, Jason;Scheuermann, Thomas H.;Anderson, Peter C.;Daggett, Valerie;Gardner, Kevin H.
缺氧诱导因子（hif）是一种异二聚体转录因子，负责后生动物缺氧反应，是肿瘤生长、转移和对癌症治疗的抵抗所必需的。HIF2α的c端PAS结构域（HIF2α PAS- b）含有一个预先形成的溶剂不可接近的空腔，该空腔结合人工配体，以变构方式干扰HIF异源二聚体的形成。为了更好地了解小分子如何在该区域结合，我们使用ITC， NMR交换光谱和x射线晶体学检查了几种人工配体的HIF2α PAS-B的结构，平衡和过渡态热力学。快速的结合率表明，尽管在核磁共振和晶体结构中观察到封闭的构象，但配体结合并不依赖于蛋白质中缓慢的构象变化来允许配体进入。补偿焓和熵对配体结合热力学势垒的贡献表明，配体结合的过渡态以结构无序性增加为特征。最后，分子动力学模拟揭示了蛋白质的开放和封闭构象之间的转换以及配体进入结合袋的途径。
Hypoxia inducible factors (HIFs) are heterodimeric transcription factors responsible for the metazoan hypoxia response and are required for tumor growth, metastasis and resistance to cancer treatment. The C-terminal PAS domain of HIF2α (HIF2α PAS-B) contains a preformed solvent-inaccessible cavity that binds artificial ligands that allosterically perturb the formation of the HIF heterodimer. To better understand how small molecules bind within this domain, we examined the structures, equilibrium and transition state thermodynamics of HIF2α PAS-B with several artificial ligands using ITC, NMR exchange spectroscopy and X-ray crystallography. Rapid association rates reveal that ligand binding is not dependent upon a slow conformational change in the protein to permit ligand access, despite the closed conformation observed in NMR and crystal structures. Compensating enthalpic and entropic contributions to the thermodynamic barrier for ligand binding suggest a binding-competent transition state characterized by increased structural disorder. Finally, molecular dynamics simulations reveal conversion between open and closed conformations of the protein and pathways of ligand entry into the binding pocket.
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影响因子：
2.9
作者：
Gong, WM;Hao, B;Chan, MK
通讯作者：
Chan, MK
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
4.4
作者：
Eyring, H
通讯作者：
Eyring, H
DOI：
10.1038/nsb0696-516
发表时间：
1996-06-01
期刊：
NATURE STRUCTURAL BIOLOGY
影响因子：
--
作者：
Feher, VA;Baldwin, EP;Dahlquist, FW
通讯作者：
Dahlquist, FW
影响因子：
5.7
作者：
Amezcua, CA;Harper, SM;Gardner, KH
通讯作者：
Gardner, KH