Department of Clinical Genetics, Meiji Pharmaceutical University, Tokyo, Japan.
J Hum Genet. 2011 Jun;56(6):440-6. doi: 10.1038/jhg.2011.36. Epub 2011 Apr 7.
Recently, pharmacological chaperone therapy for Pompe disease with small molecules such as imino sugars has attracted interest. But mutant acid α-glucosidase (GAA) species responsive to imino sugars are limited. To elucidate the characteristics of a mutant GAA responsive to imino sugars, we performed biochemical and structural analyses. Among cultured fibroblast cell lines derived from Japanese Pompe patients, only one carrying p.S529V/p.S619R amino acid substitutions responded to 1-deoxynojirimycin (DNJ), and an expression study revealed that DNJ, N-butyl-deoxynojirimycin and nojirimycin-1-sulfonic acid increased the enzyme activity of the S529V mutant GAA expressed in Chinese hamster ovary cells. The results of western blotting analysis suggested that these imino sugars facilitated the intracellular transportation of the mutant GAA and stabilized it. Among these imino sugars, DNJ exhibited the strongest action on the mutant GAA. Structural analysis revealed that DNJ almost completely occupied the active site pocket, and interacted with amino acid residues comprising it through van der Waals contacts and hydrogen bonds. This information will be useful for improvement of pharmacological chaperone therapy for Pompe disease.
最近，小分子如氨基糖类似物的药理学伴侣治疗法引起了庞贝病的关注。但是，能响应氨基糖类似物的突变酸性α-葡萄糖苷酶（GAA）种类有限。为了阐明响应氨基糖类似物的突变 GAA 的特征，我们进行了生化和结构分析。在源自日本庞贝病患者的培养成纤维细胞系中，只有携带 p.S529V/p.S619R 氨基酸取代的细胞对 1-去氧野尻霉素（DNJ）有反应，表达研究表明，DNJ、N-丁基-去氧野尻霉素和野尻霉素-1-磺酸增加了在中华仓鼠卵巢细胞中表达的 S529V 突变 GAA 的酶活性。Western blot 分析结果表明，这些氨基糖类似物促进了突变 GAA 的细胞内运输并使其稳定。在这些氨基糖类似物中，DNJ 对突变 GAA 的作用最强。结构分析表明，DNJ 几乎完全占据了活性位点口袋，并通过范德华接触和氢键与构成它的氨基酸残基相互作用。这些信息将有助于改善庞贝病的药理学伴侣治疗法。
