title: Biochemical and structural study on a S529V mutant acid α-glucosidase responsive to pharmacological chaperones.
abstract: 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.
authors.affiliation: Department of Clinical Genetics, Meiji Pharmaceutical University, Tokyo, Japan.
authors.forename: Youichi
authors.initials: Y
authors.lastname: Tajima
authors.forename: Seiji
authors.initials: S
authors.lastname: Saito
authors.forename: Kazuki
authors.initials: K
authors.lastname: Ohno
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tsukimura
authors.forename: Seiichi
authors.initials: S
authors.lastname: Tsujino
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sakuraba
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D016466:CHO Cells; D020134:Catalytic Domain / Q000235:genetics; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006009:Glycogen Storage Disease Type II / Q000201:enzymology / Q000235:genetics; D006801:Humans; D050111:Imino Sugars / Q000378:metabolism / Q000494:pharmacology; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D000520:alpha-Glucosidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D050111:Imino Sugars; D050505:Mutant Proteins; C509951:GAA protein, human; D000520:alpha-Glucosidases