title: Cloning and sequencing of the Thermoanaerobacterium saccharolyticum B6A-RI apu gene and purification and characterization of the amylopullulanase from Escherichia coli.
abstract: The amylopullulanase gene (apu) of the thermophilic anaerobic bacterium Thermoanaerobacterium saccharolyticum B6A-RI was cloned into Escherichia coli. The complete nucleotide sequence of the gene was determined. It encoded a protein consisting of 1,288 amino acids with a signal peptide of 35 amino acids. The enzyme purified from E. coli was a monomer with an M(r) of 142,000 +/- 2,000 and had same the catalytic and thermal characteristics as the native glycoprotein from T. saccharolyticum B6A. Linear alignment and the hydrophobic cluster analysis were used to compare this amylopullulanase with other amylolytic enzymes. Both methods revealed strictly conserved amino acid residues among these enzymes, and it is proposed that Asp-594, Asp-700, and Glu-623 are a putative catalytic triad of the T. saccharolyticum B6A-RI amylopullulanase.
authors.affiliation: Department of Biochemistry, Michigan State University, East Lansing 48824.
authors.forename: M V
authors.initials: MV
authors.lastname: Ramesh
authors.forename: S M
authors.initials: SM
authors.lastname: Podkovyrov
authors.forename: S E
authors.initials: SE
authors.lastname: Lowe
authors.forename: J G
authors.initials: JG
authors.lastname: Zeikus
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D003001:Cloning, Molecular; D003013:Clostridium / Q000201:enzymology* / Q000235:genetics*; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D021382:Protein Sorting Signals / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D006026:Glycoside Hydrolases; C082507:amylopullulanase