The domain-swapped dimer of cyanovirin-N is in a metastable folded state: Reconciliation of X-ray and NMR structures
The domain-swapped dimer of cyanovirin-N is in a metastable folded state: Reconciliation of X-ray and NMR structures
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DOI：
10.1016/s0969-2126(02)00758-x
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发表时间：
2002-05-01
期刊：
影响因子：
5.7
通讯作者：
Gronenborn, AM
中科院分区：
文献类型：
--
作者：
Barrientos, LG;Louis, JM;Gronenborn, AM
先前通过NMR发现有效的HIV灭活蛋白cyanovirin-N的结构是溶液中的单体和通过X射线晶体学发现的结构域交换的二聚体。在这里，我们证明在溶液中，CV-N可以以单体形式和结构域交换的二聚体形式存在。二聚体在中性pH和室温下是亚稳态的动力学捕获结构。基于取向NMR的限制，我们表明，域交换的解决方案二聚体是类似的结构，在两种不同的晶体形式，仅表现出一个小的重新取向铰链区周围。铰链中的单个脯氨酸残基突变为甘氨酸显著稳定了单体和二聚体形式的蛋白质。相比之下，相邻的丝氨酸突变为脯氨酸，导致一个专门的二聚体蛋白质，由单体的剧烈不稳定。
The structure of the potent HIV-inactivating protein cyanovirin-N was previously found by NMR to be a monomer in solution and a domain-swapped dimer by X-ray crystallography. Here we demonstrate that in solution, CV-N can exist both in monomeric an in domain-swapped dimeric form. The dimer is a metastable, kinetically trapped structure at neutral pH and room temperature. Based on orientational NMR constraints, we show that the domain-swapped solution dimer is similar to structures in two different crystal forms, exhibiting solely a small reorientation around the hinge region. Mutation of the single proline residue in the hinge to glycine significantly stabilizes the protein in both its monomeric and dimeric forms. By contrast, mutation of the neighboring serine to proline results in an exclusively dimeric protein, caused by a drastic destabilization of the monomer.