Wilson Mark A, Collins Jennifer L, Hod Yaacov, Ringe Dagmar, Petsko Gregory A
Department of Biochemistry and Chemistry and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, 415 South Street, MS 029, Waltham, MA 02454-9110, USA.
Proc Natl Acad Sci U S A. 2003 Aug 5;100(16):9256-61. doi: 10.1073/pnas.1133288100. Epub 2003 Jul 10.
Mutations in DJ-1, a human gene with homologues in organisms from all kingdoms of life, have been shown to be associated with autosomal recessive, early onset Parkinson's disease (PARK7). We report here the three-dimensional structure of the DJ-1 protein, determined at a resolution of 1.1 A by x-ray crystallography. The chain fold of DJ-1 resembles those of a bacterial protein, PfpI, that has been annotated as a cysteine protease, and of a domain of a bacterial catalase whose role in the activity of that enzyme is uncertain. In contrast to PfpI, a hexameric protein whose oligomeric structure is essential for its putative proteolytic activity, DJ-1 is a dimer with completely different intersubunit contacts. The proposed catalytic triad of PfpI is absent from the corresponding region of the structure of DJ-1, and biochemical assays fail to detect any protease activity for purified DJ-1. A highly conserved cysteine residue, which is catalytically essential in homologues of DJ-1, shows an extreme sensitivity to radiation damage and may be subject to other forms of oxidative modification as well. The structure suggests that the loss of function caused by the Parkinson's-associated mutation L166P in DJ-1 is due to destabilization of the dimer interface. Taken together, the crystal structure of human DJ-1 plus other observations suggest the possible involvement of this protein in the cellular oxidative stress response and a general etiology of neurodegenerative diseases.
DJ-1是一种在所有生物界中都有同源物的人类基因，其突变已被证明与常染色体隐性早发性帕金森病（PARK7）相关。我们在此报告DJ-1蛋白的三维结构，该结构通过X射线晶体学以1.1埃的分辨率测定。DJ-1的链折叠类似于一种细菌蛋白PfpI（已被注释为半胱氨酸蛋白酶）以及一种细菌过氧化氢酶的一个结构域（其在该酶活性中的作用尚不确定）的链折叠。与PfpI（一种六聚体蛋白，其寡聚结构对其假定的蛋白水解活性至关重要）不同，DJ-1是一种二聚体，具有完全不同的亚基间接触。DJ-1结构的相应区域没有PfpI中提出的催化三联体，并且生化分析未能检测到纯化的DJ-1有任何蛋白酶活性。一个高度保守的半胱氨酸残基，在DJ-1的同源物中具有催化关键作用，对辐射损伤表现出极高的敏感性，并且可能也会受到其他形式的氧化修饰。该结构表明，DJ-1中与帕金森病相关的突变L166P导致的功能丧失是由于二聚体界面的不稳定。综合来看，人类DJ-1的晶体结构以及其他观察结果表明，该蛋白可能参与细胞氧化应激反应以及神经退行性疾病的一般病因。
