title: Analysis of the catalytic center of cyclomaltodextrinase from Thermoanaerobacter ethanolicus 39E.
abstract: The amino acid sequences of cyclomaltodextrinase (CDase) from Thermoanaerobacter ethanolicus 39E (formerly Clostridium thermohydrosulfuricum 39E) and other amylolytic enzymes were compared by using linear alignment and hydrophobic cluster analysis. Two Asp and one Glu residue, which were considered to be the catalytic residues of the compared enzymes according to crystallographic or protein engineering experiments, were also conserved in CDase. Asp325, Asp421 and Glu354 of the CDase were individually replaced by means of site-directed mutagenesis. The mutant enzymes completely lost activity, suggesting that these residues play an important role in catalysis.
authors.affiliation: Department of Biochemistry, Michigan State University, East Lansing 48824.
authors.forename: S M
authors.initials: SM
authors.lastname: Podkovyrov
authors.forename: D
authors.initials: D
authors.lastname: Burdette
authors.forename: J G
authors.initials: JG
authors.lastname: Zeikus
mesh_terms: D000595:Amino Acid Sequence; D001421:Bacteria, Anaerobic / Q000201:enzymology*; D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016988:Gram-Positive Asporogenous Rods, Irregular / Q000201:enzymology*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017386:Sequence Homology, Amino Acid
chemical_list: D006026:Glycoside Hydrolases; C048745:cyclomaltodextrinase