title: Binding parameters and thermodynamics of the interaction of imino sugars with a recombinant human acid alpha-glucosidase (alglucosidase alfa): insight into the complex formation mechanism.
abstract: BACKGROUND
  Recently, enzyme enhancement therapy (EET) for Pompe disease involving imino sugars, which act as potential inhibitors of acid alpha-glucosidases in vitro, to improve the stability and/or transportation of mutant acid alpha-glucosidases in cells was studied and attracted interest. However, the mechanism underlying the molecular interaction between the imino sugars and the enzyme has not been clarified yet.
  
  
  METHODS
  We examined the inhibitory and binding effects of four imino sugars on a recombinant human acid alpha-glucosidase, alglucosidase alfa, by means of inhibition assaying and isothermal titration calorimetry (ITC). Furthermore, we built structural models of complexes of the catalytic domain of the enzyme with the imino sugars bound to its active site by homology modeling, and examined the molecular interaction between them.
  
  
  RESULTS
  All of the imino sugars examined exhibited a competitive inhibitory action against the enzyme, 1-deoxynojirimycin (DNJ) exhibiting the strongest action among them. ITC revealed that one compound molecule binds to one enzyme molecule and that DNJ most strongly binds to the enzyme among them. Structural analysis revealed that the active site of the enzyme is almost completely occupied by DNJ.
  
  
  CONCLUSIONS
  These biochemical and structural analyses increased our understanding of the molecular interaction between a human acid alpha-glucosidase and imino sugars.
authors.affiliation: Department of Clinical Genetics, The Tokyo Metropolitan Institute of Medical Science, Tokyo Metropolitan Organization for Medical Research, Tokyo, Japan.
authors.forename: Michiru
authors.initials: M
authors.lastname: Yoshimizu
authors.forename: Youichi
authors.initials: Y
authors.lastname: Tajima
authors.forename: Fumiko
authors.initials: F
authors.lastname: Matsuzawa
authors.forename: Sei-Ichi
authors.initials: S
authors.lastname: Aikawa
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Iwamoto
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Tim
authors.initials: T
authors.lastname: Edmunds
authors.forename: Kaori
authors.initials: K
authors.lastname: Fujishima
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tsuji
authors.forename: Kohji
authors.initials: K
authors.lastname: Itoh
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ikekita
authors.forename: Ikuo
authors.initials: I
authors.lastname: Kawashima
authors.forename: Kanako
authors.initials: K
authors.lastname: Sugawara
authors.forename: Naho
authors.initials: N
authors.lastname: Ohyanagi
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Tadayasu
authors.initials: T
authors.lastname: Togawa
authors.forename: Kazuki
authors.initials: K
authors.lastname: Ohno
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sakuraba
mesh_terms: D017485:1-Deoxynojirimycin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D020134:Catalytic Domain; D004347:Drug Interactions; D006009:Glycogen Storage Disease Type II / Q000201:enzymology*; D065089:Glycoside Hydrolase Inhibitors; D006801:Humans; D050111:Imino Sugars / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D008958:Models, Molecular; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D013816:Thermodynamics; D000520:alpha-Glucosidases / Q000378:metabolism*
chemical_list: D065089:Glycoside Hydrolase Inhibitors; D050111:Imino Sugars; D011994:Recombinant Proteins; D017485:1-Deoxynojirimycin; D000520:alpha-Glucosidases