The ALS-Associated Mutation G93A in Human Copper-Zinc Superoxide Dismutase Selectively Destabilizes the Remote Metal Binding Region
The ALS-Associated Mutation G93A in Human Copper-Zinc Superoxide Dismutase Selectively Destabilizes the Remote Metal Binding Region
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DOI：
10.1021/bi900703v
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发表时间：
2009-09-22
期刊：
影响因子：
2.9
通讯作者：
Jonsson, Bengt-Harald
中科院分区：
文献类型：
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作者：
Museth, Anna Katrine;Brorsson, Ann-Christin;Jonsson, Bengt-Harald
人类铜锌超氧化物歧化酶（CuZnSOD）基因（SOD 1）中有100多种不同的突变与家族性肌萎缩侧索硬化症（fALS）有关。这些突变蛋白的研究，这往往已经在远离生理条件下进行，表明影响油蛋白的稳定性，催化活性，金属结合亲和力，但没有共同的模式。此外，随着ALS是一种迟发性疾病的知识，很明显，在自然细胞环境中，导致该疾病的蛋白质相互作用可能取决于内在蛋白质性质之间的微妙平衡。在这项研究中，我们使用了尽可能接近体内条件的实验条件，以减少从实验装置产生的伪影。使用H-1-N-15 HSQC NMR光谱，我们分析了在野生型（wt）CuZnSOD和fALS相关的G93 A SOD变体的酰胺基团在其完全金属化状态下的氢交换。从交换模式的分析，我们已经详细描述了野生型和G93 A蛋白中所有位置的64%的局部动态。结果表明，G93 A突变对大多数研究位置的动力学没有影响。然而，突变导致突变位点的局部不稳定，并且还导致明显分散在整个蛋白质表面上的几个位置的稳定。最值得注意的是，突变选择性地使远程金属结合区不稳定。结果表明，金属结合区可能会影响分子间的蛋白质-蛋白质的相互作用，导致蛋白质聚集体的形成。
More than 100 distinct mutations in the gene (SOD 1) for human copper-zinc superoxide dismutase (CuZnSOD) have been associated with familial amyotrophic lateral sclerosis (fALS). Studies of these mutant proteins, which often have been performed under far from physiological conditions, have indicated effects oil protein stabilities, catalytic activity, kind metal binding affinities but with no common pattern. Also, with the knowledge that ALS is a late onset disease it is apparent that protein interactions which contribute to the disorder might, in the natural cellular milieu, depend on a delicate balance between intrinsic protein properties. In this study, we have used experimental conditions as near as possible to the in vivo conditions to reduce artifacts emanating from the experimental setup. Using H-1-N-15 HSQC NMR spectroscopy, we have analyzed hydrogen exchange at the amide groups of wild-type (wt) CuZnSOD and the fALS-associated G93A SOD variant in their fully metalated states. From analyses of the exchange pattern, we have characterized the local dynamics at 64% of all positions in detail in both the wt and G93A protein. The results show that the G93A mutation had no effect on the dynamics at a majority of the investigated positions. However, the mutation results in local destabilization at the site of the Mutation and also in stabilization at a few positions that were apparently scattered over the entire protein surface. Most remarkably, the mutation selectively destabilized the remote metal binding region. The results indicate that the metal binding region may affect the intermolecular protein-protein interactions which cause formation of protein aggregates.