Schäfer Patrick, Cymerman Iwona A, Bujnicki Janusz M, Meiss Gregor
Institute of Biochemistry, Justus-Liebig-University Giessen, Germany.
Protein Sci. 2007 Jan;16(1):82-91. doi: 10.1110/ps.062535307.
Lysosomal DNase IIalpha is essential for DNA waste removal and auxiliary apoptotic DNA fragmentation in higher eukaryotes. Despite the key role of this enzyme, little is known about its structure-function relationships. Here, mutational and biochemical analyses were used to characterize human DNase IIalpha variants expressed in mammalian cells. The resulting data strongly support the hypothesis that the enzyme is a monomeric phospholipase D-family member with a pseudodimeric protein fold. According to our results, DNase IIalpha contains two requisite PLD-signature motifs ((113)HTK(115) and (295)HSK(297)) in the N- and C-terminal subdomains, respectively, that together form a single active site. Based on these data, we present an experimentally validated structural model of DNase IIalpha.
溶酶体脱氧核糖核酸酶IIα对于高等真核生物中DNA废物的清除和辅助凋亡性DNA片段化至关重要。尽管该酶具有关键作用,但其结构与功能的关系却鲜为人知。在此,通过突变和生化分析来表征在哺乳动物细胞中表达的人脱氧核糖核酸酶IIα变体。所得数据有力地支持了以下假说:该酶是具有假二聚体蛋白折叠的单体磷脂酶D家族成员。根据我们的结果,脱氧核糖核酸酶IIα在N端和C端亚结构域分别包含两个必需的PLD特征基序((113)HTK(115)和(295)HSK(297)),它们共同形成一个单一的活性位点。基于这些数据,我们提出了一个经过实验验证的脱氧核糖核酸酶IIα结构模型。