title: Crystal structure of Escherichia coli L-asparaginase, an enzyme used in cancer therapy.
abstract: The crystal structure of Escherichia coli asparaginase II (EC 3.5.1.1), a drug (Elspar) used for the treatment of acute lymphoblastic leukemia, has been determined at 2.3 A resolution by using data from a single heavy atom derivative in combination with molecular replacement. The atomic model was refined to an R factor of 0.143. This enzyme, active as a homotetramer with 222 symmetry, belongs to the class of alpha/beta proteins. Each subunit has two domains with unique topological features. On the basis of present structural evidence consistent with previous biochemical studies, we propose locations for the active sites between the N- and C-terminal domains belonging to different subunits and postulate a catalytic role for Thr-89.
authors.affiliation: Macromolecular Structure Laboratory, National Cancer Institute-Frederick Cancer Research and Development Center, MD 21702-1201.
authors.forename: A L
authors.initials: AL
authors.lastname: Swain
authors.forename: M
authors.initials: M
authors.lastname: Jaskólski
authors.forename: D
authors.initials: D
authors.lastname: Housset
authors.forename: J K
authors.initials: JK
authors.lastname: Rao
authors.forename: A
authors.initials: A
authors.lastname: Wlodawer
mesh_terms: D000595:Amino Acid Sequence; D001215:Asparaginase / Q000737:chemistry* / Q000627:therapeutic use; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D006801:Humans; D046911:Macromolecular Substances; D008958:Models, Molecular; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013912:Threonine; D014961:X-Ray Diffraction
chemical_list: D046911:Macromolecular Substances; D013912:Threonine; D001215:Asparaginase